Does she have enough coolant or air in the system? See if the fans come on when the car is overheating while running. Try bleeding the air out of the system and making sure its full before you go after bigger things. It could just be the thermostat is stuck closed and isn't letting coolant flow to something as big as a blown headgasket (which it probably isn't if your mom takes care of her car and doesn't beat on it).

Grab the lower radiator hose and see if its hot.