Android Auto for passengers
Requires "AA 2nd Seat" app installed on the driver's phone running Android Auto and connected to a car.
★ Play your own music via car speakers
★ Send destinations from Google Maps to Android Auto for navigation
★ Display pictures on the Android Auto screen (e.g. the hotel, so the driver would easily find it)
More information:
https://github.com/martoreto/aapassenger
https://forum.xda-developers.com/android-auto/android-auto-general/app-aa-passenger-remotely-control-t3713198