If he has the local copies of his documents from the local Google Drive sync, wouldn't he at least have that backup, or are the local files not really files at all but just pointers to the cloud storage files? If it's the latter, does that mean that's it's literally impossible to make backups of your Google Docs documents? If I were to use a another backup program to backup my Google Drive folder, it wouldn't be poss…
But, more than that, moving the .gdoc file pointer out of Google drive moves the actual cloud file to the trash? That was my best guess after re-reading the OP, and that does seem like a UX issue. From a UX point of view, moving a shortcut to a file should not move that file to the trash somewhere else.