See Ms. Walter's answer on duplicate post.
Providing general answers are meant to help the poster to understand some complex legal concepts and in no way creates an attorney-client relationship.
No. Assuming that your brother has a security interest in the home (as beneficiary of the deed of trust), he can foreclose but only if he does not receive payments per the terms of the note. If the note has been paid promptly the only thing your son can do is to sue for partition or perhaps a liquidating receivership for the home.