Precisely. This is why I set up my non-techie clients with services like Crashplan. They do the backup consistently and automatically. Taym, I'd recommend setting your friend up (no matter how tech-friendly he may be) with the service. He doesn't have to pay to backup to Crashplan's servers, but the application will work with local storage for free or to a friend's computer that's also running the software.

It also keeps file changes and deleted files. So, if something like this happens again, he should be able to get the previous files back. I've never liked the idea of a simple mirror copy for backup purposes...