I did just think of one other thing. It is possible he is what I would refer to as a dry drunk. Sober, technically, but not working a program, hence no change in anything except his abstinence. From my experience with an alcoholic mother, that was almost worse, or at least equally bad, as her active drinking- it was MORE crazy making for our family on a whole new level.
Regardless, choosing to stay with an alcoholic is up to every individual. Just like getting into what real recovery would look like to many of us is up to every individual alcoholic.