You should find out if in her school they offer guitar lessons. They go by pretty slow, but she'll make it through. So far of my school year I've learned: C, G7, E7, B7, Am, E, Em, G, D, D7, Dm, A. It will sure help her a lot.
It also depends on the type of guitar you're having her learn on. I have a steel string guitarand I know my fingers hurt the most with that one then when I use my school's nylon guitars. They're not so hard on your fingers. And you might try getting her to learn Houndog or Eleanor Rigby, those are not very hard, and are fun to play, especially when you mess around with them using different strumming variations.