I built a digital clock for my neighbor with Alzheimer a few years ago. It was a web app with an analog clock and it would show Morning / Afternoon / Evening / Night on the side.

I felt quite proud of myself, since she often got confused about whether it was 6am or 6pm on her analog clocks at home. (Alzheimer's can bring a loss of the sense of time.)

But while she thought it was a great idea, every time I came back, she had turned off the dedicated tablet we set up for the purpose

I ended up just buying her an Alzheimer's clock — a 24 hour clock with pictures indicating the time of day, for $15 or so. That one stayed where we put it!