Im living with someone who is unstable and scares me and nobody in my family will do anything about it?

So I live with my grandmother this is my only place can stay at the moment, My cousin lives here as well who is Bi polar and has Schizophrenia. Earlier this year i pressed charges against him for sexual assault while i was sleeping. He went away for a couple weeks and now is back in the home and refuses to take his meds. He constantly threatens people like he told the lady down the street he would rip her trek out to kill her and make it seem like a accident. He walks around angry with a attitude his parents cant control him neither can my grandma. When it comes to his doctors and counselors his parents my grandmother and him all lie to make him seem like he is doing what he is supposed to do. Im afraid that any minute now he will snap and kill somebody (he tends to kill alot of animals for fun such as dogs cats mice and birds And he watches videos online about girls getting raped how to do it and how to tie girls up) or harm somebody.Im afraid of being sexually assulted again while he is in the home. Is there anything i can do to get him out the home?