Your comment about grades might not be accurate in this case. @apply2school is currently a student at a private (all girls) school, and AOs might realize this, and understand that there’s less grade inflation on the transcript.
I do think that she should “dig deeper” a determine why * she wants to apply to boarding school, given she already is a student at a private school, in a city with wonderful private schools. Finding that *why will give her direction and focus in the application process.