I'm late with this, Gardener, I wasn't online this weekend, but I'm sorry to hear about your brother, and I hope he continues to improve.
I don't think I have anything to add to the co-dependency discussion though, other than a "me too".
Oh, and the character thing- I think people have different characters within themselves (some more than others), and they carefully pick and choose which character they reveal, or how much of a particular character, to certain people. And these characters can be quite different even though they are part of the same person. Maybe that's why we get caught by surprise when they do something unexpected.
