California Code, Welfare and Institutions Code - WIC § 14008

(a) No relative, other than the spouse, shall be held to be financially responsible for the cost of health care received by an adult eligible under this chapter, except as provided in subdivisions (b) and (c).

(b) Except as provided in Section 14010, no relative, other than the parent or parents of a child under the age of 18 years, or a child over the age of 18 years if a parent claims the child as a dependent in order to receive a tax credit or deduction for purposes of state or federal income taxation, shall be held to be financially responsible for the cost of health care or related services received by such child, otherwise eligible under this chapter.

(c) To the extent permitted by federal law, the parent or parents shall have such financial responsibility for any child 18 years of age or older but under the age of 21 years who is living in the home of the parent or parents.