California Code, Family Code - FAM § 2332

(a) If the petition for dissolution of the marriage is based on the ground of permanent legal incapacity to make decisions and the spouse who lacks legal capacity to make decisions has a guardian or conservator, other than the spouse filing the petition, the petition and summons shall be served upon the spouse and the guardian or conservator. The guardian or conservator shall defend and protect the interests of the spouse who lacks legal capacity to make decisions.

(b) If the spouse who lacks legal capacity to make decisions has no guardian or conservator, or if the spouse filing the petition is the guardian or conservator, the court shall appoint a guardian ad litem, who may be the district attorney or the county counsel, if any, to defend and protect the interests of the spouse who lacks legal capacity to make decisions. If a district attorney or county counsel is appointed guardian ad litem pursuant to this subdivision, the successor in the office of district attorney or county counsel, as the case may be, succeeds as guardian ad litem, without further action by the court or parties.

(c) “Guardian or conservator” as used in this section means: