When I owned a home health and hospice in TN, this was part of orientation as well as the written policies that every nurse had to become familiar with.
Even if it means the patient drowns or dies of heatstoke, or starves, you don't take his life. You do your best to help him, and if that is insufficient, then you've done your best.
It's part of the hippocratic oath that every doctor takes or at least used to take. The classical version read, "I will neither give a deadly drug to anybody who asked for it, nor will I make a suggestion to this effect."
The modern version reads "But it may also be within my power to take a life; this awesome responsibility must be faced with great humbleness and awareness of my own frailty. Above all, I must not play at God."