I have a student with a visual impairment and she can't see the iOS app on her mobile phone. We are working to get it on her iPad but even so I don't know if she will be able to see it. Are any accommodations or settings in place to help students who need larger text?
This is usually a function of the device (hardware). In fact, iOS doesn't (or didn't - things are always changing) allow programmers to access the font size accessibility settings from within their app.
iOS 11 does have text size settings (called 'Dynamic Type'), but very few apps/websites seem to take advantage of it. (Settings / Display and Brightness / Text Size).
I just did a quick check and the only non-Apple app I have which uses Dynamic Type is EDIT: Twitter (not Facebook).
Sorry for the edit.