Honestly, I'd say this is a particularly good time to detach from the outcome of this situation, since you simply do not control it (or your AH for that matter). Yes, he may well relapse, or he may not. Not a thing you can do about it.
If he IS ready to quit, then weepy statements won't get him started. Taking action will. And again, that ball is completely in his court. He can easily find himself an AA group and/or an addiction counsellor. When a person is ready, there's no stopping him.
On your side of things, it would be wise to start attending Al-Anon to work on detaching and focusing on yourself.