Roblox will not work. The developers are actively preventing it from working in Linux.
Those other games should. If you don’t mind to tinker a bit to make sure they’re set up properly, then your son should be able to just launch them from Bottles or Lutris or whatever you set up as a games launcher.
I don’t know about Sims. I have a pirated copy of Sims 3 working just fine though.
Flatpak solves some of these. It would allow newer software on Debian. They’re packaged with codecs, so you don’t need to bother with Packman on Tumbleweed.