who do I talk to regarding mental hospital?

I have a family member who is a level 3 schizophrenia and a family member keeps getting him out. He threatened to kill my mom. He never lasts longer than 2 months and he would have a relapse. this is the second time she gotten him out. The first time he tried to kill her in Walmart. He walked off from the facility and ended up in another city hospital. He even has relapsed the last time he was out. He didn't last not even 3 months in public society without