In some states, if he has been living there the police cannot make him leave without a court order.
This is what happens when children try to play adult house. I am going to give you some unsolicited advice. Move out and never live with a man until you are married. Right now you are an unpaid prostitute. Your boyfriend has showed how important you are to him by not putting his brother out. But I bet he still wants to have sex with you.
Have more respect for yourself. THINK about these type of things before you make decisions, and consider it a good lesson learned.
"Speed is fine, but accuracy is final" --Bill Jordan
Remember those who died, remember those who killed them.