P.W.
If she wants it done permanently she can get electrolysis or laser treatments. Both aren't cheap - elect. runs approx. $35 for 15 mins., and laser probably starts at $100, but you can do a larger area. Laser usually is less effective on fine, light hair, so for upper lip elect. would be the best choice. It hurts some, but if she wants a permanent solution that's the way to go.
My chin hairs are almost gone...