The boy may be trying to escape by creating an alternate reality

 

where he is the master, in control, and has only pleasure and no pain. So the question is what he is trying to esape from?

It might help if the parents spend time with him outside of the home. Maybe start with some amusement parks and progress to playing ball and then walking in the woods. They don't have to talk if he does not want to. Just show that they care. Speak well of the community/country and his future in it. Tell him how fortunate he is to live in the present time and place. Give him hope and confidence that he is able to prosper and make a good life for himself.

The parents should refrain from talking how unfair and hard life is, how they are being treated badly by some group of people, or how they are being discriminated against by some unseen forces.  You can vent, just not around your kids. They hear everything.

Sure, if you start when the kid is seven, it would be easier than when the kid is seventeen.