Probably less "ominous" and more "got hired for something and need to clean up search results."
That just seems too good to be true, and the reason I say this is because I adore his minimalist-yet-creepy art style. To go off the radar almost completely with absolutely no trace of whatever he could be working on (might not even be illustration-related mind you) is completely bizarre given how much time has passed.
Not to mention that some of his works can be sighted in certain places, so it begs the question, "Why hasn't he contacted those sites for removal as well?" That's an elephant you can't miss.