I don’t mean new to Linux. I mean a 60 year old who is new to computers. Yes, they’ve used a computer. In an industrial setting where it runs one program all day long. But that’s it. So they have no concept of how a desktop computer operates.
Since I’m going to be teaching them, the obvious answer is use what I use. Except that I can easily pick up a different distribution if that will make the mountain they have to climb a little less steep.
Suggestions?
Probably Ubuntu or a variant thereof.
I would personally advice mint with Cinnamon, or if you feel more adventurous, maybe manjaro.
Those are the only ones I have worked with apart from Abitti, where you cannot do anything with CLI
And please don’t use abitti outside of its intended use case 
I like Zorin OS for noobs either switching from Windows or with at least some phone experience. The default version can have Windows or Touch layouts, good enough if they are familiar with Windows or smartphone/tablet like interfaces.
It’s Ubuntu based, and has been around for more than a decade. I found out about it by accident, it was preinstalled on some Acer laptop I ended up upgrading, and the person using it wasn’t even aware it wasn’t Windows.
And let’s be honest, it looks WAY better than Windows.
Another one to consider is KDE’s Neon, which is just KDE’s release of all their own tools/software and their KDE Plasma desktop ontop of Ubuntu LTS. It’s a nice little package.
Ubuntu is a staple for desktop linux OS and reasonably user experience, although I do recommend PoP_OS! over vanilla Ubuntu. I also found Zorin OS and Elementary OS very user-friendly. Your typical linux expert probably won’t use the last distros, but are worth considering for a USB pen drive full of ISOs for family and friends who aren’t into IT at all.
Since I’m going to be teaching them, the obvious answer is use what I use.
I support this answer. The best distro is the one you know well. If you like what you’re using well enough to share it, please do.