1. Verify the real estate license: you need to check the real estate license of the house and confirm the ownership of the house. If the property certificate shows that the owner of the house is himself, then he is the legal owner of the house, and the brother who sells the house has no right to interfere with his rights and interests.
2. Seek legal aid: If the property ownership certificate does not show that you are the legal owner of the house, you can seek legal aid. Please consult a lawyer and seek legal support in order to better safeguard your rights and interests.