S.C. Code Ann. § 44-77-90

After certification of a terminal condition or a state of permanent unconsciousness, any person who relies on a declaration which on its face appears to have been executed in accordance with the provisions of this chapter, of which he has no actual notice of revocation, and who withholds or withdraws or participates in the withholding or withdrawal of life-sustaining procedures from the terminally ill or permanently unconscious patient who executed the declaration, is presumed to be acting in good faith. A physician who in good faith certifies that a patient's condition is terminal or that the patient is permanently unconscious is not subject to liability merely on account of certification. Any person who in good faith and in accordance with the provisions of this chapter participates in the withholding or withdrawal of life-sustaining procedures from the patient is not subject to criminal or civil liability on account of the withholding or withdrawal. The immunity from civil liability does not extend to cases in which a physician deviates from standards of reasonable medical care in connection with the decision to withhold or withdraw.