If they run Linux, “Podcasts”, for GNOME. https://circle.gnome.org
If they don’t, well they can install it, e.g. https://fedoraproject.org or https://linuxmint.com, and sync their usual folders (~/Documents, ~/Images, etc.) to their phones by using Syncthing, so they could just check if their data is properly synchronized, and then directly install Windows, and pair back their computers to their phones.
Most people see installing GNU/Linux as a sort of long-term commitment. It isn’t. We don’t need to be fluent English speakers, or learn the CLI, or read books about system administration or software development now. It’s just a tool.
I’m concerned about being able to run GNU/Linux on computers with Pluton chips, but I shouldn’t get this hardware at home before the next decade. I’m trying to buy as much second-hand commodities as possible.