It sounds like you've tried it all. It's frustrating that at only 11, they say he can't be helped until he wants help. But he is a danger to others and himself. I can't believe I'm even suggesting this but do you feel that he and everyone else would be better off if you put him into some type of long term care? Some place where they can keep him safe and those around him safe? He has no conscience, so no regrets, and this is troubling. But you have to do what is best for him as well as yourselves. This may be something that he inherited from his biological parents. My friend raised her niece from birth, along with her other 3 children and they were treated equally. The babies mother was a drug addict and still is. My friends had to take this child to some many therapy sessions due to the things she would do out of the normal. Still with all this love, attention and emotional help, she became an addict and has been homeless for several years. She also had a baby which her step-sister is now raising, it's never ends. Adoptive children can be such a blessing, but sadly, sometimes they come with serious problems. He can't help himself, and it's very sad for all of you. I would want to put him somewhere that you can visit him and encourage him with your love, while he and others are safe, and they can help him in some way. He is reaching an age where he can do some real harm, or run away. At least you would know he is safe. My heart aches for all of you, and the decisions you have to make. This may not be the answer you were hoping for, but I don't have any ideas that you haven't already tried, and he has been diagnosed with several problems, so it's more than just a behavorial problem. I hope someone else has a better idea for you. God Bless and take care.
I went and read your profile.
It sounds like your son has reactive attachment disorder - did he have any bonding at all before he was 2 and you got him?
A really effective program for kids like him is a boot camp format rehab center. They WILL make him care what the consequences are, and will make him want to fit in.
Best wishes.