Re dementia/ end of life care, some relatives do actually want everything possible done to keep someone going, no matter how pitiful the state they're in, and get very upset or angry if anyone suggests that it might be kinder to,let nature take its course. So I think medics are sometimes reluctant to suggest it. (I can't help thinking of DM-type headlines - 'Callous doctors wanted our mum to die!')
Equally I think relatives may often be wary of questioning medics, since they think they must know best. But if you don't agree with 'striving to keep alive' I do think you have to say so.
A childless aunt of mine, mid 80s with pretty bad dementia, suffered recurrent UTIs and after the umpteenth, was refusing food and drink.
She was in a (very nice) care home, and I was asked whether I wanted her taken to hospital for drips, or left where she was, basically to die.
I could only ask the lovely GP hat he'd do if it were his much loved aunt. He said that since it was only going to happen again, probably quite soon, he'd leave her where she was, in familiar surroundings (hospital is a terrible place for anyone with dementia anyway) where they'd keep her comfortable.
It was a horrible decision, but I knew my aunt would not have wanted to be kept going in that state. She drifted away quite peacefully about a week later.