It is important to understand that unless you build an "extreme" living will (food and water denial), there are many circumstances where you will still be tortured indefinitely. I speak from family experience.
My father suffered many strokes towards the end. This caused neuropathic pain ... completely untreatable pain coming from inside his brain (primary somatic sensory cortex). He lost his ability to speak, move, and was basically just in continuous agony, only really maintaining the ability to suffer, with no hope for recovery.
Even with durable power of attorney, withholding food and water requires court orders and takes time (sometimes months)... why is making someone die horrifically of dehydration perfectly legal, but painlessly giving them a shot is illegal?
> I'd also add that this means the family members should be able to dose up grandma with enough morphine to put her out of her misery -- and I imagine such a thing happens a hell of a lot more than we will ever know
That is how my fathers suffering ended. Not by a family member, in the end it was by a nurse. The nurses and doctors and everyone seemed to give quiet nods of agreement after days of failed attempts to mitigate the constant grimace of agony. I don't think anything was ever said explicitly, but eventually a male nurse came in and made it clear that if we wanted it, today could be the last day. The decision ended up falling on me, and I said yes, the door was closed and the nurse pulled out multiple needles of something, to this day I am not sure what, but it was obviously they were packaged individually for dosage control and he had a handful of them. he slowly injected each into the IV without saying a word and my father slipped away. I am not sure I have ever been more grateful for anything prior or since.