He settled on a Dell desktop with Ubuntu, supported, (available online only) and after some questions on apps, never asked me for help afterwards.
From his and my experience: All the apps you use in daily life are there and work well. With me, Firefox and GIMP are overwhelming favorites, with DarkTable and RawTherapee in the background, should I have a tricky photo. (I don't. Nikon has been very very good to me). I rarely use "office" apps, but there's Libre Office, of course. (currently using a mac.)
Long story short, I am done with future macs thanks to Tim Cook (you know why) and developer tools have to be shoehorned into macos, and nurtured through Apple's yearly "break things" updates, whereas they are integral to Linux distros.
They are real and they are spectacular.
My fond wish: that Knoppix be updated. I have begged Klaus.
One note - a lot of the distros are Debian based (Mint/Ubuntu/etc.) vs. Red Hat (Fedora, Asahi - M1/2 Apple hardware Fedora, etc.) vs. Arch Linux.
If you're just getting started it's probably easier to get into the Debian world, but I'd advise you to dip your toes in other distros too unless you just deeply fall in love with your first pick.
(I have my 80 year old neighbor happily running Mint on their old computer to save them from having to buy a new Windows machine.)