I would say that Apple AirTags would work well, you need to attach them to their shoes or slippers as many people will takeoff tractors on a watch or clipped to their jacket but they will always put their shoes on [almost always)
If they haven't lost the ability to read yet, post-it notes stuck to the door are a good idea too.
He is your dad?
Research has shown that omega 3 oil (sardines have lots) MAY be beneficial for Alzheimer patients, this link may prove useful. https://www.sciencedaily.com/search/?keyword=Alzheimer+%2B+o... Consider music as a possible aid for the patient. https://www.healthline.com/health/alzheimers/music-for-alzhe...