Death from hunger (esp. when you're frightened and don't understand what's happening) is neither comfortable nor comforting
What you call "comforting" is leaving a helpless prison in the wilderness to succumb to thirst, hunger or predators
Go to a dementia facility and hang out with your those people. You will see suffering.
If you think that "cannot feed themselves" is when a person is already completely gone and it's okay to "leave them under a tree to die of hunger and thirst", I've got news for you.