S.D. Codified Laws § 34-12C-7
A health care provider acting or declining to act in reliance on a health care decision by a person whom the health care provider believes in good faith is authorized by this chapter to make a health care decision for another is not subject to criminal prosecution, civil liability, or professional disciplinary action on the ground that the person either had or did not have authority, capacity, or sufficient interest to make an informed health care decision or for disclosing to the person medical records or other information.
A health care provider who believes in good faith that a person is incapable of giving informed consent for himself or lacks authority, capacity, or sufficient interest to make an informed health care decision for another is not subject to criminal prosecution, civil liability, or professional disciplinary action for failing to follow that person's direction or for making such determination.
A health care provider who in good faith believes that a person is capable of giving informed consent for his own health care is not subject to criminal prosecution, civil liability, or professional disciplinary action for following that person's direction or for making such determination.
A person who in good faith believes that he is authorized under this chapter to make an informed health care decision for another is not subject to criminal prosecution or civil liability on the ground that he lacked authority or capacity.
SDCL 34-12C-7