Legal Question in Family Law in California

The answer depends on how the title is listed. There are many ways to designate the title to real property, but the most common ones are "joint tenancy" and "tenancy in common." With a joint tenancy with two people, when one owner dies, the other owner automatically gets the entire title. With a tenancy in common with two people, when one owner dies, the deceased owner's share is distributed according to law. With no will, the share would be distributed to the deceased person's heirs (e.g. spouse, children, parents, etc.).

I have described only one scenario for each of the most common ways to hold title to property. There are many other possible scenarios. It would be worth the money for your sister and boyfriend to check with a real estate attorney about how to properly list the title. An attorney who deals with wills and trusts could be helpful, as well.