It is awful to hear. I am sorry you're going through all these. You have the last resort if needs be, instead of calling the police, some welfare home or nursing home can do this for you at a fee. What I am saying is if your elder brother continually poses a threat to your family, you and your father can send him to the welfare home for long stay.
As far as I know, private welfare home in the suburbs of KL is not cheap, at or above MYR 1000 monthly. You also can refer to psychiatric clinic in government hospital for referral to the welfare home or nursing home.