(a) This part is supplemental and alternative to other procedures or methods for obtaining consent to health care or making health care decisions, and is permissive and cumulative for the relief to which it applies.
(b) Nothing in this part limits the providing of health care in an emergency case in which the health care is required because (1) the health care is required for the alleviation of severe pain or (2) the patient has a medical condition that, if not immediately diagnosed and treated, will lead to serious disability or death.
(c) Nothing in this part supersedes the right that any person may have under existing law to make health care decisions on behalf of a patient, or affects the decisionmaking process of a health care institution.