What a train wreck.
He refuses to speak, because he is either so low functioning he's frustrated, or he's learned he doesn't have to speak.
Ditto with the work.
Of course he has other learning disabilities. He has whatever it takes to get him through.
A good friend's son is on the spectrum; she mentioned once that he could get into university with accommodations, but she felt he probably wouldn't be able to handle it. That was a huge, huge step as a parent, since she was a die-hard supporter of her college. She made it all about her son and not her own dream.
My guess is Nazir is rebelling by refusing to do anything.