Continuing government contracts, expectation of favours in return, they almost certainly hold some dirt on him (and many others).
1) So what would motivate him?
2) How often do these type of "exchanges" go on, and we have no idea someone's (e.g., politician, journalist, industry titan, etc) actions were dictated by the Intelligence Community? This isn't a conspiracy theory. It's IC 101.
As far as what would motivate him: look at what's happening to Musk right now as an example. I'm not saying he doesn't comply and cooperate with law enforcement, but he's certainly being made a big example of right now from all sides.