Is there someone who can stay with you while you're waiting for your brother to arrive? Is there a friend you can stay with until your brother gets there? I'm just a strong believer in strength in numbers, and in finding a "safe house."
My mother, sister and I were terrorized in this way when I was growing up, and there was little recourse. Police did not involve themselves or sometimes take seriously "domestic" disputes in those days. Those memories are terrifying and horrifying to me, and so I get scared all over again when I hear what you're experiencing. Sorry to sound frantic, just want you and your children to be safe and take all precautions.