I don't know...
After reading those plays it doesn't seem to me like he was abused, other than him abusing himself in his own mind.
He seemed more delusional than anything else.
He was probably quiet all the time because he was suffering from auditory hallucinations and wasn't sure which voices were real and which ones were
the delusions.
He probably didn't even know how to respond.
His writings did seem like the result of some kind of psychosis, and very disassociative too.
They didn't really make much sense to anyone other than him, it's as though he left parts out because he could hear it and see it in his mind and
didn't feel the need to record it all on paper. Like the world was sharing his delusion so he wouldn't have to go into deep detail.
He did seem very angry, which is usually characteristic of such severe delusions.
Well, either way, it's sad all around.
Starting from this tormented kid, to those he hurt.
We're going to be feeling the after-effects of this for quite a while.