Windows 8 almost destroyed my computer-illiterate father-in-law so I suggested he try Linux Mint and after a while he agreed. He was fine for the 3 or so years he used that laptop. There was an issue with it like 2 years after I did the install regarding the official repos being outdated and keeping regular updates from running but that was the only time I really had to mess with it for him.

I did my own distro hopping years ago and eventually settled on Linux Mint personally and I feel like it's probably among the better options for "just works" out of the box for people wanting to take the leap. I do know a lot of people praise Fedora with KDE too but I just never really got around to checking it out personally so can't vouch.

Even if you are computer illiterate, most stuff you need will be the official software center(repositories) of whatever distro you go with and it's all basically a one button click to install these days. But also command line isn't super scary either, but you mostly don't even need to use it for just everyday stuff.