The health care powers that may be delegated to an agent include, without limitation, all powers an individual may have to be informed about and to consent to or refuse or withdraw any type of health care for the individual. A health care agency may extend beyond the principal's death if necessary to permit anatomical gift, autopsy, or disposition of remains. Nothing in this chapter shall impair or supersede any legal right or legal responsibility which any person may have to effect the withholding or withdrawal of life-sustaining or death-delaying procedures in any lawful manner, and the provisions of this chapter are cumulative in such respect.