California Code, Probate Code - PROB § 1502

(a) A nomination of a guardian under this article may be made in the petition for the appointment of the guardian or at the hearing on the petition or in a writing signed either before or after the petition for the appointment of the guardian is filed.  The court shall give due weight to the nomination of a guardian of the person pursuant to Section 3043 of the Family Code.

(b) The nomination of a guardian under this article is effective when made except that a writing nominating a guardian under this article may provide that the nomination becomes effective only upon the occurrence of such condition or conditions as are specified in the writing, including, but not limited to, conditions as to the subsequent absence, legal incapacity, or death of the person making the nomination.

(c) Unless the writing making the nomination expressly otherwise provides, a nomination made under this article remains effective notwithstanding the subsequent absence, legal incapacity, or death of the person making the nomination.