welcome to Healthcare Magic.
is a chronic and severe psychiatric disorder. I can understand your concern regarding your brother illness. The basic pathology in this illness is increase dopaminergic neuro-transmission in brain.
It is treatable condition and behavior improved after treatment. It is treated with medicines which decrease dopamine neuro-transmission.
This condition should be treated after adequate assessment by treatment with medicines (like antipsychotics).
In symptomatic phase of illness patient do not have insight regarding illness, so they deny for treatment, in such cases depot injections or medicines in food are helpful.
Wish you all the best.
Dr Ashish Kumar Mittal