(a) The provisions of this article are cumulative with existing law regarding an individual's right to consent to or refuse medical treatment. The provisions of this article shall not impair any existing rights or responsibilities that a health care provider, a person, including a minor or an incapacitated person or a person's family may have in regard to the withholding or withdrawal of life-prolonging intervention, including any rights to seek or forego judicial review of decisions regarding life-prolonging intervention under the common law or statutes of this state.
(b) This article creates no presumption concerning the intention of an individual who has not executed a living will or medical power of attorney to consent to, refuse or withdraw any and all medical treatment or diagnostic procedures, including, but not limited to, life-prolonging intervention.