I should add, that while I understand the dilemma of having a lot of hair, make sure the helmet fits your friend's head snugly. The padding compresses a little after a few times making the helmet of little looser. If you are jumping, you do not want that to happen. I say this as someone who twice road XC courses and one stadium course with my helmet tipping down over my eyes. Very dangerous and annoying to say the least. Try to find one with extra space inside, but make sure it is snug where it counts.
You just have to see your distance...you don't have to like it.