I had a phone with one on the back and currently have one with it on the screen. Personally I had absolutely no issues with its functionality in the screen and do prefer it over the back. I like that I can unlock my phone without having to pick it up off the desk or while its still in the mount on my vehicle dash.
Seems to work perfectly fine to me but maybe it’s a quality issues with the brand of phones. Mine is a OnePlus and it’s almost 4 years old now, still works fine and never had any issues.
Then what’s the issue? If he doesn’t then the person living with him should be doing the driving.
Unless they are also elderly and unable to drive safely. Then they should both be selling the farm and moving somewhere closer to town/services.