Cal. Prob. Code § 3707

For the purposes of this chapter, any property or interest therein or lien thereon that the absentee holds as joint tenant shall be included in determining the property of the absentee and its value. The joint tenancy interest may be set aside to the family of the absentee as provided in this chapter but may only be set aside to a member of the absentee’s family who was a joint tenant with the absentee in the property.