If we are aware that someone’s children have signed a DNR which does not faithfully represent the person’s wishes, but rather the family’s wishes, we know what theoretically we have to do – according to the law of the land. We have to let authorities know (right now, not when the person is in arrest). Secular law is far from perfect but it has provisions for these situations. If the patient is fully of sound mind, he/she will state or write down his wishes for medical care and EOL in front of the required witnesses; otherwise the court will appoint a guardian who will be in charge of deciding, after having consulted the family and the rabbi or whoever else the patient indicates he trusts. Most ignore this law despite it being there. Is it Obama’s fault too?
I would not call the nurse nor the hypotetical person in Health’s examples “un-human”, but one can not blame their own decisions on someone else always. Choices usually come at a price.