Health Care Representative, Eligibility
Any competent adult may serve as a health care representative, with the exception of any attending physician or health care provider who provides the principal with health care services and is not related to the principal by blood, marriage, or adoption.

The chosen health care representative is not required to have a family relationship with the principal, but a family member may be chosen.

Living wills are not required to designate a health care representative and the absence of a designation does not affect the validity of a living will.

However, in the absence of a designation or if the designated health care representative is not reasonably available, Pennsylvania law provides that any member of the following classes may be designated to serve:
1) The principal's spouse and the principal's adult children who are not also children of the spouse, if any
2) An adult child
3) A parent
4) An adult sibling
5) An adult grandchild
6) An adult who has knowledge of the principal's preferences and values, including religious and moral beliefs, to assess how the principal would make health care decisions

When the principal has not designated a reasonably available health care representative, individuals are chosen upon the basis of priority, as listed above. (Meaning that a reasonably available parent will be designated before an adult sibling, and so on.)

See: Health Care Representative, Role and Duties