That is not his claim at all. Read the lawsuit.
.https://www.courthousenews.com/wp-content/uploads/2018/03/aaron-rich-DC-suit.pdf
Would "zero hours" be "countless hours"?
I think he’s looking to cash in any way he can. https://www.washingtonpost.com/news/local/wp/2018/03/27/brother-of-slain-dnc-staffer-seth-rich-sues-right-wing-activists-newspaper-over-conspiracy-theories/?noredirect=on&utm_term=.c31171050b6e