Does your mom have a keychain with lots of heavy keys or other keychain "knick-knacks"? If so, she's probably broken her ignition lock cylinder. This is really common, you might need to have that ignition lock cylinder replaced. What happens is that after awhile, the keys bouncing up and down actually loosen the cylinder and make the contacts not line up properly. Believe it or not, my mom did the same thing to one of her cars.