Customise Android phone for someone with Dementia

I have a parent with Dementia, who has always struggled with technology but we need a way of - Calling them - Tracking them - Allow them to make calls They do not need all the functionality of a smartphone but I am hoping I can setup one in a way that would help them. The Android Find My Device would allow us to find them when they wander off, so the only other functionality I want is to make a call and answer a call, that is it. It needs to be very easy because if they find themselves in some menu somewhere they cannot find there way back, so I want to hide everything else. I wanted a couple of pictures on the phone they can tap to call that particular person and an easy way to answer an incoming call. Is there a way I can configure or setup a phone in this way. I am pretty technical (software developer) just don't actually know much about phones. Can I even write some software to achieve this? Any help would be appreciated. We have tried old fashioned non-smart phones but even those are too complicated, they have to open contacts, find the person, press a button to make a call etc, because with dementia they cannot remember any instructions, and that is too much, it needs to be very very intuitive and limited.