450K is a bit much...but if my son was murdered and I had some f***stain like this guy running around saying my kid wasn't killed i'd want to f*** his life up. Best way to f*** someone's life up is to extract a painful sum of cash from them.
If he legitimately proved slander damaged his reputation and deprived him of some economic opportunity (like say he lost a job over it etc) then depending on whatever calculation was used to arrive at that number, 450k isn't a lot of money. not to mention half of that is probably going to the attorneys anyways.
-Mike