This is why self-hosting matters. Why distributed version control is more resilient. I haven’t yet used it but this is the sort of use gave for Radicle where folks seed the repo like a torrent & there is no meaningful centralized server that you could even go after.
I mean the IBM PC was standardized but you are welcome to install whatever video card or as much or little RAM as you want which means developers can’t specifically target your setup (with fewer testing Linux), but a lot of things not requiring the bleeding edge run just fine. Unattended upgrades is a good idea, but that is if the distro supports it—and that’s still a better experience than Microsoft Windows updates.
If it’s set up correctly. The biggest selling point of a console is that it boots you to “play game” mode as the default & games have better expectations since the hardware is standardized. That said, in the case of Steam, there’s nothing to say you can’t install Linux & have it boot directly into Big Picture mode (but you’ll still need to remember to get software updates for the OS as they aren’t integrated like a console).
Don’t do Minecraft when Minetest is open source. It’s not meant to be installed as vanilla per se tho as mods are for building gameplay and vanilla is just a sandbox/canvas to build Minecraft-like or addjacent games. Especially if you can get him on PC, I could be a hopskip away from creating his own open mods (as opposed to the content farm of underpaid “devs” for Roblox which have wild stories if you look it up).
Veloran is also a good alternative for free software with an adventure MMO aspect that might appeal to the guy.
Being projects without a profit motive & a strong community where the players are the developers is a safer route where you would never expect loot boxes, microtransacitions, dark/addictive patterns because those aren’t fun & money isn’t an incentive. With the source available your son is more than welcome to read it to figure out how games work, contribute ideas/code, & learn to make mods which are all great, real-life skills learned while accidentally gaming & trying to make the game better for yourself & friends—and if he’s not a future coder, there are assets & stories to build, or just playtesting a friend’s mod.