We have been quietly killing off some elderly and disabled for a long time now, hidden away from the public view, by denying them nourishment and hydration. I believe, but don't have stats, that some cancer patients are deliberately overdosed with chemo and possibly morphine to speed along the death process. It is seen as more merciful, and indeed it may be, but it is still playing God.
The only case I cold endorse for pulling a feeding tube *might* be in some medical conditions where pumping liquid food into a cancerous stomach or hydration would cause more pain and discomfort in the terminally ill.
I agree with all you said in your post #68. Thanks for understanding.
No need to be iffy. The right criteria are really very simple. Water should be given as needed to prevent dehydration. Food should be given as needed to prevent starvation or malnutrition. Really very simple.
To get slightly more detailed, if a person's kidneys are functioning, they will continuously extract water from the blood it will be necessary to replace that water. If a person's kidneys have stopped functioning, the body will not lose water nearly as fast and will have no way to rid itself of excess water, and so much less water will be needed to prevent dehydration that continuing to add water to the body would cause problems of its own.
Even without such detail, though, the principle is very simple and should be applied consistently.