Is alcoholism treatable?

my partner was a very successful businessman up until just over 2 years ago when for many reasons the business was forced to cease operating. He had always been a big drinker when the business was going well, but was always always a happy drunk.Since everything went downhill he has kept drinking as before but he has become a nasty angry sometimes threatening man when under the influence, who is now being treated for depression to deal with all the issues he has had to face in the last 2 years. Things are beginning to come good for us again, but the stress of the last 2 years and his depression has really taken its toll on me and i realy need to know that if everything starts working again and the business is given another go, and is successfull, do you think his attitude and personality will return to what it was before or will he continue to be this person. I dont know if i could continue to live like this if he never gets back to himself.please please help