Legal Question in Wills and Trusts in California

I'm not sure based on the limited facts you have provided. At first glance, it sounds as though your step brother and brother owned the property as joint tenants. Joint tenancy is distinctively characterized by the right of survivorship. What that means is when one joint tenant dies, thant that owner's interest in the property will pass to the surviving owner or owners by operation of law, and avoiding probate.

To clear title after the death of a joint tenant, the surviving joint tenant records an affidavit of death of a joint tenant, which shows that record title is now in the name of the surviving joint tenant.

If this is not what you mean, or what happened, then you may need to repost with more factual information.

Mr. Roach is correct. You do not state that you asked your step-brother why he felt he can make the transfer.