Having been an oncologist and having cared for scores, if not hundreds, of dying patients, when you don't have a treatment that can shrink the tumor and the patient will die, it's a very difficult conversation. It's emotionally draining.
Doctors take the Hippocratic Oath too seriously, as an imperative to do everything for the patient regardless of the cost or effects on others
An obvious example is not guaranteeing health services to patients with dementia.