As long as the engine wasn’t starving for oil under load (i.e. the oil pressure warning light did not come on), she won’t have done immediate, catastrophic damage. I would worry more about the cumulative effect of five years of chronic neglect. After the car is fully warmed up, does the light come on at idle? If it does, the engine is on its last legs.
At this point, your aunt has two options:
(1) Since it still runs, trade the car in on something better. This will only work if it isn’t obviously in distress.
(2) Continue driving the car until it dies. Expensive repairs, that would be a justifiable investment in a well maintained car, would be a waste of money with this one. Your aunt should get a AAA membership, always carry a charged cell phone and avoid lonely places late at night.