I loved Magic Tree House at his age! That’s exactly what I was thinking—MTH is wonderful for escapism. If you can get him onto something that exercises his mind, that’s the ideal, hence my drawing, reading, and chess suggestions—anything he can sustain in isolation and when low on funds or access to shops.
Edit: magic tricks if he’s dexterous!
Unfortunately his mother is still his guardian, so she may very well one day pick up and leave with him. In that situation, at least he’ll have the skills to keep growing his interest(s) and entertain himself.
I was sent to a series of the ‘better’ programs—i.e., the ones without deaths attached to them. It took a decade of therapy to deal with the worst of the trauma and I still experience PTSD episodes several times each year. It’s astounding how these facilities carry on functioning with merely a name change. There’s almost no regulation, let alone patient rights. My first program was truly one of the better ones and they had patient rights information posted through the facility and hard copies provided in your welcome packet. When I was sent to my second program (wilderness), I asked what my patient rights were. I received dumbfounded stares followed by laughter.