A very sad but all too common story. I would suggest taking a look in the friends and family forum for other folks with similar experiences. If it was me in your shoes, he would be gone. But that is what I would do, not necessarily what you should do. Perhaps a family lawyer can offer you some advice?
This is a nasty illness. What you describe is the progression of the disease. Hopefully it will lead him to a point where he can overcome his aversion to mixing with the common folk and perhaps acquire some humility. In the mean time, try not to enable his behaviour. He is a sick man, but that is no excuse.