How about getting him into a mental institution instead of sending him back to Russia by himself?
They don’t have many in-patient facilities anymore....why do you think there are so many mentally ill homeless people. They are especially lacking when it comes to children. You cannot just drop the kid off and say here...they won’t take them!!!
Have you ever tried getting a 7 yr old into a suitable group home? It's very, very difficult. It takes months, IF you can even find a place that takes kids that age. Better to get them out of the home before someone is hurt or killed.
I teach these kids, and I've gotten to see the system work and not work close up.