I had a kitten that bit, I always used a toy to play with her, never my hands. I bought a "da bird" wand toy (cheaper wand toys will work as well) and played with her with it, very few kittens can resist them. Playing with her for about 10 minutes would tire her out, I'd give her a rest for a few minutes and then play with her for another 10. Cats are sprinters rather than marathon runners so two short play sessions will be more than enough, she'll be ready to eat and then sleep.
Another thing great thing I bought was a Kong Wubba for kittens (again, any soft toy that the kitten can chew would be fine). Your friend can may wish to keep it close, and when the kitten becomes aggressive, distract it with the toy. My cat loved hers and would carry it around from room to room, bite it, bunny kick it and even sleep with it.
I have tried the method where, where when the kitten bites you tell it "No" in a firm voice (or hiss) and walk away, as the mother cat does. Kittens have very short short-term memories, your friend only needs to ignore her for a few minutes. I had limited success with this method only because you have to be consistent or else it won't work. Unfortunately, my partner wouldn't come to the party and tended to let her get away with it. The good news is that she did grow out of it, I think by the time she was about 8 or 9 months old?
I would not encourage your friend to grab her by the scruff of the neck or raise your voice, I've read that this method is going out of fashion with behaviourists as it makes the kitten scared of you and quite possibly more aggressive.