Even easier (from the user's perspective) solution: 1. Make a photo of her own radio. 2. Put that photo on a tablet device. 3. Allow her to click on the photo where the buttons are. 4. Adjust stations/volume accordingly. Next step: physically operate her own radio remotely :) Or: let her bring her own radio, and use internet and an FM transmitter to relay the signals.
The tablet never unlocks, so you don’t have to worry about UI quirks.