(a) A health care power of attorney is a durable power of attorney. Statutory provisions that refer to a durable power of attorney or judicial interpretations of the law relating to durable powers of attorney apply to a health care power of attorney to the extent that they are not inconsistent with this part.

(b) This section does not affect the right of a person to execute a durable power of attorney relating to health care pursuant to other provisions of law but which does not conform to the requirements of this section. If a durable power of attorney for health care executed under this part or under the laws of another state does not conform to the requirements of this section, the provisions of this section do not apply to it. However, a court is not precluded from determining that the law applicable to nonconforming durable powers of attorney for health care is the same as the law set forth in this section for health care powers of attorney.

(c) To the extent not inconsistent with this part, the provisions of the Adult Health Care Consent Act apply to the making of decisions by a health care agent and the implementation of those decisions by health care providers.

(d) In determining the effectiveness of a health care power of attorney, mental incompetence is to be determined according to the standards and procedures for inability to consent pursuant to § 44-66-20(8), except that certification of mental incompetence by the agent may be substituted for certification by a second physician. If the certifying physician states that the principal’s mental incompetence precludes the principal from making all health care decisions or all decisions concerning certain categories of health care, and that the principal’s mental incompetence is permanent or of extended duration, no further certification is necessary in regard to the stated categories of health care decisions during the stated duration of mental incompetence unless the agent or the attending physician believes the principal may have regained capacity.