I use several of the suggestions above, but also for IOS (iPhone) I use “Firefox Focus” and it clears everything when I close it and I can watch ad free.

I have been able to play most games fine on Linux mint.

If he plays Minecraft bedrock he can use “Minecraft bedrock launcher” which loads the android version (if you own it on the play store). Minecraft Java works find on Linux, but I prefer bedrock to use a controller.

Some PC games I play in “bottles” which lets you run windows programs.

I also have “heroic games launcher” that lets me play epic games, gog games and Amazon games.

I remember when I setup my Wordpress website years ago I had permission errors, so the Wordpress install needed read/write access to the website directory. Maybe the same in your case?