The friend could have misunderstood what the priest said, possibly?  She, or you, misinterpreted what he said?  Also, most priests (a) forget quickly what is said in the confessional, since they hear so many confessions, (b) are actually not all that interested in remembering the sins they hear, let alone repeating them to others (because of the severe punishment).  I mention that because you said,

"It was exactly what I had told him in confession the previous day."  [bolding mine]

Given how quickly priests forget, it would be extraordinary to remember a verbatim confession, and to care enough about remembering it to share it with a third party, and then third to risk his own excommunication.
Keep in mind that priests hear repeated patterns of sins-- from many parishioners -- in the course of even a single month.  Some sins are so common that they could be "lifted" from any random person's confession without the priest intending to identify anyone -- that's how common they are.  And he is covered, canonically, for doing that, by the way -- IOW, for saying things like, "Anger is the most frequently repeated sin in my confessional."  Priests are allowed to speak vaguely of generic sins confessed without identifying a particular confession moment or a particular penitent.

So be careful of repeating things you heard from a third party -- about anyone, but certainly about this matter, because of the severe consequences to the priest and to his reputation.  I'm not saying that I "know" that it didn't happen, but I am saying that it is unlikely that a priest would recklessly mention your specific confession to a third party, and there is a great risk here of calumny or detraction.

I know of what you speak.  There is no mistake, I can assure you.  This particular priest absolutely, without a doubt in either my mind or my friends mind, broke the confessional seal.  I pray for him often.

I have never personally had the seal of confession broken with me, but the priest we use to see would always make comments to everyone “oh I truly know this person, because I hear their confessions!” And give like this almost making fun of the person laugh. It felt like whatever you said in confession was stored in his head to be kept for later. It was scarey going to confession after a while.


I honestly can’t imagine why people want to know anyone else’s confessions... I don’t even want to know my husbands confession because it’s all I can do to keep myself out of trouble lol I can only think that they do it to make themselves feel better about their sins, but not realizing they are committing a sin by doing that. 

...the priest we use to see would always make comments to everyone “oh I truly know this person, because I hear their confessions!” And give like this almost making fun of the person laugh. It felt like whatever you said in confession was stored in his head to be kept for later. It was scarey going to confession after a while.

For a while? 
I would not go to confession with that priests anymore.

I know of what you speak.  There is no mistake, I can assure you.  This particular priest absolutely, without a doubt in either my mind or my friends mind, broke the confessional seal.  I pray for him often.

You do not "absolutely without a doubt" know unless you confront the priest, preferably with your friend as witness, to ask him to verify that he did or did not reveal a particular sin that you told to him within the sacrament only (without not also mentioning it outside of the sacrament during direction, a private meeting, etc.).  He will ask what you are talking about.  You will repeat what your belief is, based on this third party's version of what he said.  He will then ask the friend to recount the conversation between him and her, such as, 'You, Father, discussed TxTrad's sin that she confessed just a few days ago,' and precisely as she confessed it. You [brought it up out of the blue]" -- difficult to believe, by the way; priests have better things to do -- or "[you, Father, responded to a question of mine about sin in general, and you chose to insert into our conversation a particular sin a penitent, my friend, had just revealed to you in the holy sacrament of Confession.]"

Etc.  There are obviously other scenarios, but none of them are believable to me, because they all assume far too much, to wit....

The confessor has a morbid interest in your personal sins, outside of the confessional, and is willing to risk his position and his standing with the Church, just to satisfy his morbid interest.

In turn, that would mean that he has an intense, spiteful, or vengeful dislike of you for some personal reason such as some "bad blood" between you and him.  But it would have to be pretty extreme for him to risk so much just to indulge a capital sin of Anger, Envy, etc.  There are a lot of jerky priests within the Church, although they are a minority, but very few of the worst jerks would jeopardize their position unless they were already on the way out, by their own choice or someone else's.  And he knows darn well he will have to answer to a very justly angry Second Person of the Trinity for indulging a vice at the expense of his own soul and in violation of a sacred trust.  I don't care what trad or N.O. seminary he graduated from; he knows it.

Alternately, the priest thinks so highly of your friend that he figured he could "score some points" with her by revealing a sacredly privileged secret.  If so, either she is someone very important in the parish -- so much so that he found it useful to ingratiate himself to her by going so far as to risk his soul and his position, or he has a personal stake in his relationship with her.  Men are more prone to sudden heart attacks than women are, and often those first heart attacks are final heart attacks.  He would have to think very highly of your friend to make such a foolish error, particularly because he would also know/assume that she would repeat it to you -- assuming he knows you two are friends.

Less far-fetched (slightly, but only slightly more believable) would be if he repeated your sin to another priest.  That would be less risky to him because he knows that other priests know what canon law binds them to, as well as what it bound your confessor to.  Therefore, unlike your friend, any priest hearing your sin outside of a confessional would not be so foolish as to repeat the sin that was revealed.  Your friend seriously compounded the problem by either misunderstanding a general comment to equal a specific revelation, or she participated in the same hypothetical evil he committed by then detracting against him.  Detraction is a mortal sin.  If she were so convinced that what the priest said was an actual unlocking of a secret confession, she should never have told you.  She should have brought the situation to her own confessor to ask for advice on how to handle it.  If I were she -- your friend -- and I was absolutely convinced that this was a deliberate breaking of the Seal on the priest's part, I would not have gone to you, but I might have gone to my bishop if a (obviously different) confessor did not satisfy my sense of Catholic morality.

At the very least, she participated in backbiting, which is a specific sin, and in this case a very serious level of backbiting.  Possibly she participated in calumny or detraction.  And if she misunderstood what he said, she threw you into a great deal of anguish about this, anguish of soul, anguish of heart and mind -- threatening not only your relationship with this priest, but possibly your confidence in approaching the sacrament, period.

You do not "absolutely without a doubt" know unless you confront the priest, preferably with your friend as witness, to ask him to verify that he did or did not reveal a particular sin that you told to him within the sacrament only (without not also mentioning it outside of the sacrament during direction, a private meeting, etc.).  He will ask what you are talking about.  You will repeat what your belief is, based on this third party's version of what he said.  He will then ask the friend to recount the conversation between him and her, such as, 'You, Father, discussed TxTrad's sin that she confessed just a few days ago,' and precisely as she confessed it. You [brought it up out of the blue]" -- difficult to believe, by the way; priests have better things to do -- or "[you, Father, responded to a question of mine about sin in general, and you chose to insert into our conversation a particular sin a penitent, my friend, had just revealed to you in the holy sacrament of Confession.]"

Etc.  There are obviously other scenarios, but none of them are believable to me, because they all assume far too much, to wit....

The confessor has a morbid interest in your personal sins, outside of the confessional, and is willing to risk his position and his standing with the Church, just to satisfy his morbid interest.

In turn, that would mean that he has an intense, spiteful, or vengeful dislike of you for some personal reason such as some "bad blood" between you and him.  But it would have to be pretty extreme for him to risk so much just to indulge a capital sin of Anger, Envy, etc.  There are a lot of jerky priests within the Church, although they are a minority, but very few of the worst jerks would jeopardize their position unless they were already on the way out, by their own choice or someone else's.  And he knows darn well he will have to answer to a very justly angry Second Person of the Trinity for indulging a vice at the expense of his own soul and in violation of a sacred trust.  I don't care what trad or N.O. seminary he graduated from; he knows it.

Alternately, the priest thinks so highly of your friend that he figured he could "score some points" with her by revealing a sacredly privileged secret.  If so, either she is someone very important in the parish -- so much so that he found it useful to ingratiate himself to her by going so far as to risk his soul and his position, or he has a personal stake in his relationship with her.  Men are more prone to sudden heart attacks than women are, and often those first heart attacks are final heart attacks.  He would have to think very highly of your friend to make such a foolish error, particularly because he would also know/assume that she would repeat it to you -- assuming he knows you two are friends.

Less far-fetched (slightly, but only slightly more believable) would be if he repeated your sin to another priest.  That would be less risky to him because he knows that other priests know what canon law binds them to, as well as what it bound your confessor to.  Therefore, unlike your friend, any priest hearing your sin outside of a confessional would not be so foolish as to repeat the sin that was revealed.  Your friend seriously compounded the problem by either misunderstanding a general comment to equal a specific revelation, or she participated in the same hypothetical evil he committed by then detracting against him.  Detraction is a mortal sin.  If she were so convinced that what the priest said was an actual unlocking of a secret confession, she should never have told you.  She should have brought the situation to her own confessor to ask for advice on how to handle it.  If I were she -- your friend -- and I was absolutely convinced that this was a deliberate breaking of the Seal on the priest's part, I would not have gone to you, but I might have gone to my bishop if a (obviously different) confessor did not satisfy my sense of Catholic morality.

At the very least, she participated in backbiting, which is a specific sin, and in this case a very serious level of backbiting.  Possibly she participated in calumny or detraction.  And if she misunderstood what he said, she threw you into a great deal of anguish about this, anguish of soul, anguish of heart and mind -- threatening not only your relationship with this priest, but possibly your confidence in approaching the sacrament, period.

You make a lot of assumptions and extrapolate many conclusions based on very little information I provided.  You were not there.  You have no idea what you are talking about.  If anyone is causing calumny or detraction it is you.
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I know for a fact, beyond a shadow of doubt,  he broke the seal of confession.  I will not discuss it further.

I don't think I would go to his mass, either.  Intent would come into question.

We haven’t been in almost two years... 

 I seem to recall the sentence was automatic in the 1917 code.  No matter...  God will sort it out.

Latae Sententiae means that the excommunication is automatic.