@Ananse It's reasonably likely that the company uses some kind of version control. But given the time, it's also likely that it required some extra hurdles to activate, so one would only use it on finished documents (tracking updates and versions, not work in progress), whether company policy allows it or not. (It's so much easier to just have a personal copy to work at, then deliver once it's done.)
Having a hundred pages lost though.. yea, he should have been checking in at least a couple times during that period. XD