Schools don't want to have to replace broken personal iPads, however, like was asked above- how have they been ensuring that your child has access to the educational curriculum since your child began school? Did they complete an AT eval initially?
I agree w/ Angela and I'd have a conversation with the teacher/support staff and let them know that this is what your child needs; you've provided it; and you'd appreciate them using it in the classroom. I've seen too many children go years without access to appropriate AT. If your child knows how to use the app, let the teachers know that and share success you've seen at home. If you have any friends in the tech office at your district, see if they can help you expedite their review. Another idea is be to reach out to the district's sped director and let them know that you've purchased this, your child needs this based on (whatever private evals/progress data/etc. you have), and that you'd appreciate their help doing anything they can to expedite the process. Sure, the process can take a long time, but if people want to help, things can sometimes happen quickly. You're simply asking for your child to be able to access their educational environment.