It's your house correct? Tell your brother to get his own place, if he doesn't get a court order to get him out. Your house your rules, I wouldn't take any type of abuse from anyone.
I take care of my dad who is living with me I also have a brother who is living with me and he continues to badger my dad and my dad wont do anything about his abusive behavior. What can I do I'm afraid of the brother cause he is nuts?