If the button on the key is not working and does not unlock your car door, you can put the key in the little hole and unlock the door.
Seriously, had to show a poor young girl in the mall parking lot one day how that works on Daddy’s Tahoe.
They’re not putting lock cylinders on some vehicles these days and some only have 1 on the driver side door. They’ve been working on that for years, slowly phasing them out.
“you can put the key in the little hole and unlock the door.”
Pretty sure you can’t do that on our cars.
Better yet…teach them to read the manual. There are all sorts of neat things in my Silverado manual about what to do when fob batteries fail. This is important when you have keyless ignition.