This is a sad and hopeless situation.

I can see that the mother's solution to chain her son for a 'medical condition(?)'

is for just in case the son loses control and causes harm to others.

Is there 'medical' treatment for his condition, other than 'sedating shots' and chains?

(Public) Mental health services in this case seems so far from ideal.

No. I don't have an answer.

Does anyone have an answer?