[zozbot123]

> The PC I'm assembling is for an 80yo guy who doesn't trust the internet

Why are you setting this guy up with Windows 10 then, instead of a system that actually respects the user and has decent security, like Debian GNU/Linux? (There is an enduring notion that Debian systems are hard to install or administer for the casual user, but one might argue that it is 5 years out of date - maybe even 10 years out of date.) Does he rely on some Windows-only hardware or software of some sort - and if so, could he run that on a dedicated, airgapped system?