Allow me to share a personal view - take it or leave it as you see fit.
A few years ago I had a VERY severe case of pneumonia - and was intubated for 6 days (life support). The machines breathed for me, fed me, etc.
During that time, I was in and out of consciousness. Being unconscious was better. When I was aware, I could not communicate (tubes down my throat, body and arms and legs restrained, etc.).
The pain of the tubes is beyond description. It is surpassed when incompetenet hemotology techs do bad Arterial Blood Gas tests. Don’t open the spoiler if graphic descriptions bother you.
An Arterial Blood Gas test involves inserting a hypodermic needle in an artery. .not a vein. Arterys have nerves - veins don’t. Arterys are deep, veins tend to be on the surface. They are supposed to inject novocaine first - sometimes there is not enough, often the just miss the artery. Also, very often, they miss the artery, and have to keep going in again and again. When I was on life support, I had this test EVERY SIX HOURS around the clock.
With all the pain, fear, horror, etc that I experienced… not knowing how long it would last or whether I would live or die, I NEVER FOR A MOMENT WANTED ANY OF THE TREATMENTS TEST ETC to stop. Pain is transitory - death, as far as I know, is permanent. Screw the pain. If they needed to, I would have wanted them to take any measure at all, regardless of pain or suffering, to save my life. I am thankful to them that they did.
Footnote - I go for surgery next week. They asked me to sign the “heroic measures should not be taken” thing. I laughed at the admissions clerk and ripped it up. Then I told her “been there, done that” and she understood.
I understand why some people have a tendency to give up. But for some of us, we ain’t going nowhere till we are good and ready.