A hallucination can be very real to a person who has Alzheimer’s disease. Caregivers should respond to such events with calm, gentle and reassuring words and gestures. The goal is to support the person’s feelings without agreeing with the hallucination. If a hallucination is disturbing the Alzheimer’s patient, check the environment for noises that might be misinterpreted, lighting that casts shadows, or for reflections or distortions from the surfaces of floors, walls and furniture. For example, a patient might insist that the person in the mirror is a stranger. It’s possible that they no longer recognize their own reflection. To ease their anxiety try covering up or removing the mirror.
(Source: Alzheimer’s Association)