He sent his hard drive in to recover data, it's entirely plausible that they ran a scan of unallocated space, got a bunch of files, then looked at them to check

He sent his hard drive in to recover data, it's entirely plausible that they ran a scan of unallocated space, got a bunch of files, then looked at them to check if they were corrupted (very often recovered files only have a tiny bit of the original file), and found they were corrupted in a very different way.