well, if you want to understand more about alcholism, you could go over to the alcholics forum on SR.
it sounds from what you've said (please correct me if i'm wrong) that he had a previous problem with alcohol and went into recovery with AA. then, he saw himself slipping, and went back to AA?
if that is so, there is some chance that this problem is bigger than he let on during your relationship and he knows himself how far he can fall, as he's been there before.