(a) If any person is a minor or an adult where a valid declaration does not exist and a healthcare proxy has not been designated and who, in the opinion of the attending physician, is no longer able to make healthcare decisions, then the declaration may be executed in the same form on his or her behalf by the first of the following individuals or category of individuals who exist and are reasonably available for consultation:
(1) A legal guardian of the patient, if one has been appointed;
(2) In the case of an unmarried patient under the age of eighteen (18), the parents of the patient;
(3) The patient's spouse;
(4) The patient's adult child or, if there is more than one (1), then a majority of the patient's adult children participating in the decision;
(5) The parents of a patient over the age of eighteen (18);
(6) The patient's adult sibling or, if there is more than one (1), then a majority of the patient's adult siblings participating in the decision;
(7) Persons standing in loco parentis to the patient; or
(8) A majority of the patient's adult heirs at law who participate in the decision.
(b)
(1) Even if an advance directive that includes a directive to withhold nutrition or hydration, or both, is signed by a person under this section, if the terminally ill patient requests nutrition or hydration, his or her wishes shall be honored.
(2) Unless the use of artificial means is specifically requested, a patient's request for nutrition or hydration, or both, shall not be honored by use of artificial means if doing so would require the insertion of any apparatus into the patient's body.