Your getting yourself all worked up over it isn't going to change a thing. If he wants to, he will drink, regardless of what you put yourself in a panic over.
You are too emeshed in his issues, might be time to let go of them and work on your issues, there is a reason that you obsess, dig deep and find out what it is.
Keep those meetings up, have you read Codependent No More? It is a good starting point.