Cal. PROB § 2355

(a) If the conservatee has been adjudicated to lack the capacity to make health care decisions, the conservator has the exclusive authority to make health care decisions for the conservatee that the conservator in good faith based on medical advice determines to be necessary. The conservator shall make health care decisions for the conservatee in accordance with the conservatee’s individual health care instructions, if any, and other wishes to the extent known to the conservator. Otherwise, the conservator shall make the decision in accordance with the conservator’s determination of the conservatee’s best interest. In determining the conservatee’s best interest, the conservator shall consider the conservatee’s personal values to the extent known to the conservator. The conservator may require the conservatee to receive the health care, whether or not the conservatee objects. In this case, the health care decision of the conservator alone is sufficient and no person is liable because the health care is administered to the conservatee without the conservatee’s consent. For the purposes of this subdivision, “health care” and “health care decision” have the meanings provided in Sections 4615 and 4617, respectively.

(b) If prior to the establishment of the conservatorship the conservatee was an adherent of a religion whose tenets and practices call for reliance on prayer alone for healing, the treatment required by the conservator under the provisions of this section shall be by an accredited practitioner of that religion.