Hello! Welcome to HealthcareMagic! I have gone through your questions and understand your concerns. In my opinion, presently your brother is suffering from paranoid type of schizophrenia. The symptoms you gave in the history like hearing voices, suspension that someone going to harm him, aggressive and irritable behavior all coincide with the above diagnosis, I mentioned before. These symptoms are a part of the disease itself. If I were your treating psychiatrist, I would advise immediate pharmacological treatment with anti-psychotics like Olanzapine or Risperidone depending upon patients history and symptoms. Medication ought to be used continuously for 1-2 years, if it s 1st episode. Schizophrenia, is a chronic disease where patient s compliance is poor regarding continuous use of medications as they won t feel that they are suffering from a disease. Hope this clarifies your concerns. Thank you for the query. Take care Regards, Dr. Bhagawan Rajana, Psychiatrist