(a) A duly appointed guardian for the principal shall comply with the principal's preferences or instructions expressed in the advance mental health care directive and shall not revoke the principal's advance mental health care directive, unless otherwise expressly authorized by a court of competent jurisdiction.
(b) Absent a court order to the contrary, a mental health care decision of an agent takes precedence over that of a guardian.
(c) A mental health care decision made by a guardian for the principal is effective without judicial approval, unless contrary to the principal's preferences or instructions expressed in the advance mental health care directive.