It means if there is a situation occurs that would end life such as a stroke or cardiac event, no heroics or treatment should be undertaken. It does not mean pump the old guy with phenobarbital and morphine until he flatlines. As far as I am concerned, they should rot in H3ll for the implication.
A power of attorney is a legal document that allows someone to make financial and legal decisions for you.
And it goes without saying that these documents best be reviewed by a lawyer and certified. Can you just download a form from the internet for free? Sure, but as they say, you get what you pay for.
Disclosure: After my wife passed away last year intestate, I made darn sure I had all four of the above taken care of.
Doctors ignore both the living will and the power of attorney
In my neck of the Upstate woods it’s called a MOLST. And it’s different from a DNR. Our family members have had both. FWIW. :-)