Incorrect, but good, theory.
Sadly, the entire theory of the kid being the little brother or son of the purple guy is debunked due to this easter egg that shows the actual purple guy . Also, not entirely proven, but from this easter egg it appears that this isn't the bite of 87, but instead some other bite
Also, I don't ever take any theories mark says seriously cause he hasn't been right once in the entire series. I love mark, but he is not good with the theories.