I tried doing that for my family and iOS has this wierd restriction where it drops all incoming calls automatically when you use Kiosk/SingleApp mode. Even if FaceTime is open in foreground.

You could also limit the iPad to running Facetime only in Apple Configurator.

That's exactly the case where iPad starts dropping calls.

Oh. Kinda makes sense, but bad restriction in this case.

Or PineTab with a browser in kiosk mode (Surf?) pointing to a meet.jit.si room :)

It's a breeze to set up with NixOS as long as you're not afraid of the command line, and easy to remotely manage with SSH and fully reproducible configuration. Hit me up for a free sample VM :)

This sounds like a great setup. Never heard of PineTab before - is the CPU powerful enough for live video encoding?

May be a little too underpowered actually.

There was a recent forum thread with users claiming the Pinebook Pro is somewhat usable with Jitsi Meet; and the Pinebook Pro has a more powerful CPU in it than the Pinebook which has the same chip as the Pinetab.

Maybe going with a refurbished Surface or similar would be a better option; talking to an elderly relative is an use case that hardly calls for open hardware.