I agree with the other posters. It appears your detaching is having a positive effect in that he is realizing that you are establishing boundaries and expecting him to live his life differently.
In the old days I was at my XA's side everytime the doors were open at his many rehab stays and the message I sent was that any time he made recovery noises or took actions towards recovery I would pretzel myself into what I considered total support of that action.
Years later I now analyze my actions and his behaviors and see a completely different picture and wish I had could do over those years of the hovering, helicoptering codie.
What I taught him was that relapsing was not a big deal because once he came up for air from his boozing all he had to do was check into a rehab to reel me back in like a fish on a hook.
Secondly, rehabs are just sober geography and the real recovery takes place when they leave the sober environment. If they don't plug into a recovery program that has accountability and creating an environment of self inspection and willingness to change everything... I mean everything... then they will drink again.
AA works if the A gets a sponsor that knows the steps and the A dives into the program (not just the meetings which are just fellowship and encouragement)....
If the A doesn't change on the inside and deal with the core issues that cause them to drink they will drink again... AA can be the path or a really good counselor that knows addiction has helped many A's overcome their addiction.
There are other groups but there needs to be a support network and growth ... if that doesn't happen the vast majority stay on the chronic relapse rat wheel.