personality disorder

My brothers wife has personality disorder. She tried to suicide by scratching her arm with medicine cover and tried to accuse my mother of violence. Then her father came straight from Karachi and threaten us to keep her daughter here in home. My mother denied then he put on an act, break glass and strike it on his forehead saying he would call police and accused my mother of murder attempt. He also verbally abused us a lot. My mother immediately then lock herself in a room to remain save. We tried our best to resolve the dispute through dialogues but they’re now become a threat for our own lives. My brother resides abroad. He called and said that he’s preparing visa for her wife until she must leave my mother’s house but still they are not moving rather threatening us. How can we legally seek help and protection?