Well 3pin you're in a bad way for sure. At this point I'm back to suggesting backing up the data via iCloud then resetting the iPhone to see if that fixes it after the iPhone is reset.
You can try removing the apps she installed but I doubt that'll change anything, honestly.
Otherwise make a reservation at a Genius Bar:
www.apple.com/retail
Not much else we can try over the forums, someone who knows the hardware needs to get their hands on the device. Knowing Apple's SOP regarding these kind of things I'd still encourage you to do that Erase All Content and Settings after doing an iCloud backup (make sure you set it up as a new iPhone once reset, if you do) - Apple like any other computer company wants to elimnate software issues. If you don't do it then the Geniuses will do it before they look at servicing the hardware of the iPhone.
Sorry 3pin. Wish there was more I could do. Unless someone else drops by with advice then that's all I've got. I've done some searches online & am not seeing anything different than what we've tried.
Good luck! And when you get it solved let us know.