This might sound strange, but just looking at this situation from another perspective. I would agree with the third comment, i.e. it would be impossible for a Protestant to be in such a case unless he was mentally handicapped. We also should consider that the Protestant religion is totally repugnant to the natural law. Only a person of bad will would believe that he could commit such and such a sin without any sort of punishment. Humans intuitively know that God rewards good and punishes evil.

Adults (i.e. those at the age of reason) do not receive sanctifying grace without a cooperation of the will and proper disposition of the intellect.  Infants receive these as infused virtues without said cooperation, but adults cannot.

This is taught clearly by the Council of Trent.

So, what's MORE at issue is whether a Protestant is capable of having supernatural faith.  That is the real question.  Baptism by itself does not put him into a state of grace that remains until mortal sin ... if he is not capable of having supernatural faith.  So I think that this is the wrong question.  We need to discuss whether or not it is possible for a Protestant to have supernatural faith.

I hold that it is not possible for a Protestant to have supernatural faith.  Now, is it possible that there's some person so befuddled and so ignorant that he does have the core basics of the faith in such away that it's not uprooted?  I cannot necessarily rule that out.  But in that case, he would in fact be a Catholic and not a Protestant.  But I would consider this ... if it's possible at all ... to be incredibly rare, and I hold that God WOULD in fact lead such a one into the Church if he were properly disposed in this way.

So, for instance, let's say some Prot minister goes to the jungle, teaches a person about the basics, the Holy Trinity and the Incarnation, and then proceeds to baptize him after he comes to believe him.  This person has no clue about there being Catholicism or Protestantism or any other such details.  At that point, the baptized man is a Catholic.  But as soon as he begins to learn about the various Prot heresies that uproot faith, then he would lose the faith.  Is there some Prot who's so ignorant and befuddled that he's in a similar state as this savage in my example, who just knows the basics and hasn't had his faith polluted and uprooted by heresy?  In other words, can there be such a thing as a Prot who's a purely-material heretic?  As I said, I can't rule it out, but believe that God leads all of His elect into the visible Church.  But those Protestants who believe in faith alone and Sola Scriptura are formal heretics because they have their belief system founded on a false rule of faith that ultimately reduces to their own private judgment.  Formal heresy deals with the WHY of belief, while material heresy deals with the WHAT of belief.  If you had a Protestant who just so happened to believe every single Catholic doctrine because he deduced them from the Bible, he would still be a formal heretic, since the REASON he believes them does not suffice as the formal motive of supernatural faith.  He would merely have a correct natural faith, but not a supernatural faith.

This is taught clearly by the Council of Trent.

Same would apply of the Orthodox.  Is it possible that there's some Orthodox out there who's so confused and befuddled that his schism and heresy are purely material?  Perhaps.  But I should think it incredibly rare.  But then he would in fact be a Catholic and not Orthodox.  If, however, he's not Catholic, then he would go to hell.  But if he is Catholic, then whether he went to Purgatory would depend on his degree of culpability with regard to his material errors (and of course his other sins).

Wrong thread.  This discussion is about someone already baptized.

Such a one, by virtue of Baptism, belongs to the Church soul and body ... and is in fact a Catholic.

Did you read that in a Catechism or a Manual, or is it your home-baked theology? The 1917 code plainly says that such persons who are in good faith are still yet not given the Sacraments - which shows they do not belong to the Body of the Church; for if they did, then they could not be denied the Sacraments.

So, what's MORE at issue is whether a Protestant is capable of having supernatural faith.  That is the real question.  Baptism by itself does not put him into a state of grace that remains until mortal sin ... if he is not capable of having supernatural faith.  So I think that this is the wrong question.  We need to discuss whether or not it is possible for a Protestant to have supernatural faith.

I hold that it is not possible for a Protestant to have supernatural faith.  Now, is it possible that there's some person so befuddled and so ignorant that he does have the core basics of the faith in such away that it's not uprooted?  I cannot necessarily rule that out.  But in that case, he would in fact be a Catholic and not a Protestant.  But I would consider this ... if it's possible at all ... to be incredibly rare, and I hold that God WOULD in fact lead such a one into the Church if he were properly disposed in this way.

So, for instance, let's say some Prot minister goes to the jungle, teaches a person about the basics, the Holy Trinity and the Incarnation, and then proceeds to baptize him after he comes to believe him.  This person has no clue about there being Catholicism or Protestantism or any other such details.  At that point, the baptized man is a Catholic.  But as soon as he begins to learn about the various Prot heresies that uproot faith, then he would lose the faith.  Is there some Prot who's so ignorant and befuddled that he's in a similar state as this savage in my example, who just knows the basics and hasn't had his faith polluted and uprooted by heresy?  In other words, can there be such a thing as a Prot who's a purely-material heretic?  As I said, I can't rule it out, but believe that God leads all of His elect into the visible Church.  But those Protestants who believe in faith alone and Sola Scriptura are formal heretics because they have their belief system founded on a false rule of faith that ultimately reduces to their own private judgment.  Formal heresy deals with the WHY of belief, while material heresy deals with the WHAT of belief.  If you had a Protestant who just so happened to believe every single Catholic doctrine because he deduced them from the Bible, he would still be a formal heretic, since the REASON he believes them does not suffice as the formal motive of supernatural faith.  He would merely have a correct natural faith, but not a supernatural faith.