To be completely fair, I'd recommend you install them something like Linux Mint Debian Edition (because Ubuntu might not be that great), or any other beginner-friendly Linux distribution depending on their needs. They need to realize that Windows is already malware, and Linux is the best solution they have. Otherwise, they can buy a Mac, and that's a bad ecosystem you don't want to be in (as an Linux guy and an iOS user, not a good combo for me).