Don’t know how to help you with those vdi problems, but here is an out of the box thinking: tell him to ask a neighbor.

I have a similar situation so i got a hetzner VM and set up wireguard connections from both ends, so that vm serves as a hub/router. Then you can just ssh into the machine via vpn and do an update, upgrade or whatever.

If you stick with Ubuntu lts, it will require very little maintenance.

The question is if they will close that 15-20y gap in 3-5y