This is a terrible situation far all involved. Whether you believe this child is autistic or sociopathic if you have dealt with this then you know that treatment is sparse and long term residential facilities for children are all but, nonexistant. There are a few but, ins doesn't cover it and of course they are cost prohibitive.
The current treatment rubric is to wait for the child to attract the attention of law enforcement, proceed to juvenile detention and then adult level incarceration.
Mental health options are woefully lacking.