During the program it is referenced that he often writes severely complex pieces which "even" he cannot play. I would suggest to you that these pieces are dreck.
You may have noticed that almost all his pieces are "fugues", which suggest to me that someone led him to this format and this is basically all he can focus on. Not exactly exactly music.
Is he smart? Yes. Is he nice? Yes. Is he a genius, I don't know. Just seems like a musical prodigy.
His strength was presented as music composition, rather than playing the concert piano.
Those are two significantly different musical processes if you ask me.
I have a 9 years old grandson who is a fine pianist/composer for his age. His compositions are generally a little beyond his physical ability to play ... interesting phenomena.