So far I haven't seen a copy of the lawsuit and the "seven claims for unspecified damages," so take this for what it's worth. The first defense filed in literally every civil lawsuit is some version of Plaintiff has failed to state a claim upon which relief can be granted. In simple English, it means that even if everything Gruden alleges is considered true, he still hasn't stated an actionable claim.
"In contrast to the formalities of the Washington Football Team investigation, Defendants' treatment of Gruden was a Soviet-style character assassination," the lawsuit says. "There was no warning and no process. Defendants held the emails for months until they were leaked to the national media in the middle of the Raiders' season in order to cause maximum damage to Gruden." OK but so what? Just because Ginger Satan and the Snyders did him dirty, doesn't mean he's entitled to relief. I'm definitely looking forward to reading the lawsuit to see how he gets there.
Where Chucky has all his leverage is in discovery. If he can survive a Motion to Dismiss, he can presumably get to the 500K+ emails and start taking lots of depositions. The NFL will do anything to stop that from happening, including paying him off.