I think using a floor bar is helpful to use at home to work on this. Straddle the bar with feet on floor and then press to handstand to get the straddle motion that is used. If she can do a squat on or pike on, a helpful way to think of the skill is that you are doing a pike on but then straddling your legs before your feet get the bar. This is close to the correct motion that is needed in terms of lifting your hips and getting the butt above the bar.