I feel like he has a machine that someone set up for him, and he can’t escalate permissions, because he’s on a basic user account.

The normal way this works on a single user machine is:

1. You try to do something that is restricted to admin
2. Windows puts up a modal dialogue box asking if you want to do it as admin
3. You click yes
4. You do it as admin

But in that case he can’t have locked himself out of a file, he can only be locked out of things Microsoft think you shouldn’t muck with unless you know what you’re doing