Seriously. Just do it.
Patient W sat in our ICU for weeks, never better, but never worse enough to declare himself. He had lived for 15 years with his wife and her daughter. They were at his side throughtout his ICU stay. They were his family, without any legal rights. His biological family was a hot mess. Security was called on them several times. His DPOA fell to his mother, who had dementia. He was not legally married and had no legal children, so that's the way it was. The family didn't like his significant other or her daughter, but then, the family was never around him while he was alive. But they felt so important once he was mostly dead and they were being asked to make decisions on his behalf.
If you want someone to speak for you or have a say in your medical care when you cannot, for god's sake, get the paperwork done. You may not like whose lap it falls into!
Eventually, the patient declared himself and died. The daughter of his long-term partner, who was his daughter in every way but blood, called and specifically asked for me (when I was caring for a different patient). She wanted to tell me how much my care had meant to her and her mother. They had stopped coming into the hospital because of the crazy family drama, and because they knew he was gone but couldn't bear to watch his body suffer. They had said their goodbyes and knew that he knew he was loved by them.
So sad. I'm so honored to have given them what little comfort I could.