I think there have been many tragic stories where well-meaning white people have adopted a black child in hopes of giving it a better life then end up realizing what a huge mistake that was when the grown up child physically attacks them, steals from them, etc. no matter how well they were raised.
I think the foster-parents are guilty, because they had to show him love, but also a hard hand.
If someone comes from an evil culture and was raised in it a few years, he/she needs to rebooted. This works.
Tell him about god and what he likes and doesn't like and be everytime an example. Also educate him in the bible and try everything, that he will find a place in your religious community.
There are lots of positive examples. Bolschewiks should denied to be foster parents, because they even don't know who they are themselves.
Only fundamental Jews and Christians should be allowed to challenge this difficult task.