If they are willing and able to learn something with a radically different interface: Fedora.
If they aren’t: Linux Mint. There is nothing easier for a former windows user than Mint and it has a ton of built in tools for any kind of user. Not to mention forums support and massive package repos (+ built in flatpak).
I swear by Linux Mint - it's easy to setup and it required basically no transition for me at all coming from windows to get used to the controls and layout, was very painless.