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 :)
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.