What are the best exercises for an overweight client who lifts her heels when she does a squat? Thx!

I am with Sue in limiting squats with the very overweight. I do find success having them squat against the wall with a stability ball behind their back. Even with that they often do not go very low. As Michael said it could be related to tight lower legs, but could also be a lat and or lower back flexibility issue as well.