All diets allow for more than just apples to be fed - she will need to be cautious that her diet mix itself doesn't incorporate apples in any form(juice, applesauce, apples, etc.) which probably leaves HPW as the best option :) There are fruit & veggies relishes(set mixtures that provide the proper ca:ph ratios) or if she is sure to offer a variety incorporating some of the higher calcium foods, she should be good!
Just so its out there, BML allows more than just apples to be fed - it allows for a variety of melons(watermelon, cantaloupe, etc.), berries, grapes as well as apples (but it does use apple juice in the mix, so I understand her avoiding it).