Hi Sir My Brother Was Addicted Of Drugs (specially Sholpha

Hi sir

My brother was addicted of drugs (specially sholpha etc) but now he not taking anything and remains at home all the time. He did not speak with any family member. He never laugh and be happy. The major problem he always fight with his wife even beat her inhumally the reason he never disclose but we know he thinks that wife is not loyal and two kids are not of his.
Sir, is this any mental I'll and also is this curable?

Regards