I agree with jennie. If a person has an alcohol problem, it doesn't absolve him or her of responsibility for his or her actions. S/he chose to take that first drink in his/her life and chose to drink to excess, leading to a problem. As Ben said, your wife does need to take responsibility for getting help.

If drinking meant you could get out of your responsibilities, then we could just get drunk before going to work, babysitting, or doing anything, so if something did go wrong, we could just say, "Sorry, not my fault. I was drunk." It just doesn't work like that.