It's not uncommon to have prolific inventors in companies like IBM or so. Maybe the company realised that this person's patents were not worth enough, however,

It's not uncommon to have prolific inventors in companies like IBM or so. Maybe the company realised that this person's patents were not worth enough, however, they might turn valuable in a few years, who knows, through some acquisitions, etc. The sad thing about these situations is that the inventor is not owning the patent, the company screwed the engineer, and this is now on his/her own trying to fight legal battles. In my opinion, the best thing to do in such situations is to leave your job and make a startup. If this guy is able to fill 30 patents he has probably some good ideas.