In general I would recommend any Debian derivate for beginners that just don’t care about how their computer is operating. So if this is really just a question regarding eight Fedora or Linux Mint then I would say Linux Mint because it’s a Debian derivative.
That’s simply because chances are high stat you will at least find a Deb package for any proprietary software you might want to use. Making it “easier” for the user.
If you install the system for your friend you’re free to change the Desctop environment to everything you want.