johnno1, I think all of us here have seen our A's do exactly what you're describing. It is so very, very unlikely that he can just put the bottle down and miraculously turn into the man of your dreams, at least for any length of time.
You're right, time will tell.
And I would advocate still getting to Alanon b/c you'll need the tools and support you will get there when (and I do say when, not if) he returns to his old habits. What's the worst that can happen if you go? You spend an hour meeting some nice people and getting some insight on better ways to deal with life and its problems...not a waste of time, no matter what.