Night of the Broken.

In 1965, a Jewish doctor, Gertrude Rosen, is called to a remote care home in England to help identify and treat a dying patient. As Gertrude slowly wins the patient's trust, she discovers the horrible truth of who he is, and faces an awful dilemma. To help end his life peacefully, or let the monster suffer in pain like the millions of her people who died at his hands.