NTT,
Everything you are discribing, while heart-breaking is "to be expected" considering what he has gone through. For now, You be his best friend. Hire bright teenagers to "babysit" him and be his friend. Recruit every Adult who is in the picture to do one-to-one time. You tried the playdate route, ok, it's failing, he's still mourning, that's ok.
He isn't being abnormal in anyway. This will take time. I am sorry it's bad, but relieved that he's out of there. We still think that they are too young to suffer so, but they aren't.
Love and More Love (because that is what this will take)
Trinity
