BIking has actuallly helped my patella femoral pain (I agree it sound like she has it ) - so I'd get yourself fit to your bike or have someone knowledgable help you with it.

If my bike is "perfect" my knee doesn't hurt - if my seat position is off or anything like that, I can flare up my patella femoral syndrome.

Way back when I did physical therapy to strengthen my inner thigh muscles to help with the patella femoral and the therapists taught me how to tape my knee cap into the right position until I got the muscles balanced out... and in general the therapy was effective even though I didn't keep up with the exercises afterwards.

But my knee would still flare up on long hiking or backpacking trips or ski vacations - since I've started biking, I don't have those flare ups anymore...