Yeah, there's that idea, the good man idea. Equally plausible is the idea that working as closely as he did with Trump, he knows how irrational Trump is. He may well have figured that his odds of going to prison as a traitor to his country would be non negligible if he went along with Trump's crazy plans.

Choosing not to act in a reckless manner is ordinary human behavior. I would say that's the likeliest explanation for why he didn't try to invalidate the election.