first off, have her get it scanned like you told her to.
are the fans working when the a/c is on?
and do the fans come on when the engine gets warm? with out the a/c being on?
sounds like it could be a bad temp sender. it located under the t stat in the manifold. the wires also could be fubared as the exhaust is right there to cook the wires.
the scan will tell you more tho.