Yes, he was 80 when he was in lock up treatment and became sober for the first time in his life. We were in different towns and I just saw them a couple times a year until he was 80. He always was a functioning drunk, held a job, but moved us yearly probably because he didn't pay rent, more money for drinking that way. (See my blog) I was so surprised when he died that so many people, relatives too, liked him. I never thought that they didn't know what he was really like. They do have a good act going on don't they?
I'm sorry you have to go through all this. I think emotionally disconnecting is vital as is forgiving the undeserving parent for our sake. See our stickies above if you haven't already.