Just a couple thoughts to consider:
Does your therapist know thoroughly how Al-Anon works? It may be time for a new therapist who can take you further.
Just be aware his drinking, or not, may have little to do with true inner change. The personality patterns that led him to drink are still there unless he does his own work on it.
You'll find much support and growth for yourself in Al-Anon and learn excellent communication skills with a good therapist.
Wishing you well....