my wife's best friend is an alcoholic, now she's asking me to talk to him as she's ready to file for divorce. She has threatened for a couple of years now so he probably just thinks she's bluffing. Apparently it's not a bluff. Her whole family is now telling her to leave him, and some of them used to tell her to stick with him .
She hired some ex alcoholic to do some kind of intervention and even he old her there's no hope wit him. I will talk to him but doubt I can convince him of anything, it's not like we're really close. He tells her he will get  help but from what I can gather he hasn't gotten any. He owns an Irish bar. I don't see any hope unless he sells the bar.
 Besides telling him he will go to hell for being a drunkard not sure what else I can add. If anyone has any ideas I'll take them

My brother died at 57 from alcohol.
There is nothing you can say, do, threaten, bargain, manipulate, plead, shame etc that will get him
to stop until he wants to stop.

The church allows separation for drunkeness.

Tell her to take the children away from him

Then pray for him.

Well said. Support isn't support for a drunk, it's "enabling". Tell him to pray the Rosary, three Aves, something. He likely won't now, but may later AFTER the pain of loss is greater than that he's drinking away now.

Support HER. Help HER, so that she can do the right thing, including pray for her husband. After that, he'll either get it together, or he won't. 

Caveat: don't assume that demonic isn't at play here. If available, and being a lush seems like danger of death to me, they can last ditch try to avail themselves of whatever VALIDLY ordained priest, preferably traddy, preferably (don't hold your breath on this one) an exorcist just to check the boxes if naught else.

Prayers: Blood/family in particular can do bindings/adjurations/abdurations. 

Basics: Are they Catholic? Are they baptized? Has their environment been blessed, consecrated etc. etc. etc....

She should seek advice from a traditional priest. Please don't pass along Forum advice as it may be incorrect for the particular situation and could lead to worse things. No one on the forum knows the particulars so the advice given is worthless. 

If they have to be Cathlic, "rotsa ruck"

She should seek advice from a traditional priest. Please don't pass along Forum advice as it may be incorrect for the particular situation and could lead to worse things. No one on the forum knows the particulars so the advice given is worthless.

Yes your advice is worthless.
Who better to give advice than someone who has lived with drunkeness for decades, researched,
kept hospital vigils, cleaned up after, prayed and prayed and prayed to no avail.

What can a priest who has no knowledge and experience with drunkeness offer but prayer..
The church allows separation for drunkeness.  Even if she gets a civil divorce to protect the children and assets,
she is still only separated according to the church.

Isn't this forum to help people with our experience?

A priest could give her moral guidance that would keep her from sin which you can't do.

I agree completely.
I was speaking of practical/legal/coping advice which is what I understood the OP to be requesting.
I assumed like anyone here on a Catholic forum that spiritual and moral issues are taken to the priest.

My brother died at 57 from alcohol.
There is nothing you can say, do, threaten, bargain, manipulate, plead, shame etc that will get him
to stop until he wants to stop.

The church allows separation for drunkeness.

Tell her to take the children away from him

Then pray for him.

thanks for the advice, no children, they are novus ordo catholics, the church allows separation for drunkeness? I always thought only fornication was a reason to separate..if the drunkeness leads to her not being safe then I agree, separate, but if it's because of his getting drunk at the bar now and then I don't know that I can recommend separation, he can go a month without taking a drink, then he just falls back on the wagon, gets drunk, doesn't come home

he can go a month without taking a drink, then he just falls back on the wagon, gets drunk, doesn't come home

.
How does he get drunk when he falls back on the wagon?