(1) A person authorized to consent to health care for another may exercise the rights of that person under this chapter to the extent necessary to effectuate the terms or purposes of the grant of authority. If the patient is a minor and is authorized to consent to health care without parental consent under federal and state law, only the minor may exercise the rights of a patient under this chapter as to information pertaining to health care to which the minor lawfully consented. In cases where parental consent is required, a health care provider may rely, without incurring any civil or criminal liability for such reliance, on the representation of a parent that he or she is authorized to consent to health care for the minor patient regardless of whether:

(a) The parents are married, unmarried, or separated at the time of the representation;

(b) The consenting parent is, or is not, a custodial parent of the minor;

(c) The giving of consent by a parent is, or is not, full performance of any agreement between the parents, or of any order or decree in any action entered pursuant to chapter 26.09 RCW.

(2) A person authorized to act for a patient shall act in good faith to represent the best interests of the patient.