So, I sent the petition to my brother (the lawyer) -- waiting to hear back, which is weird because he'll probably ask me what I think (I helped him study for the bar exam, for fun

because I'm way better at constitutional law than he is)
Heller is using 2 different defenses here: in the first case, he's trying to nullify the contract (more about that later) and in the second he's trying to use the same defense that many whistle blowers have used (and they also signed confidentiality agreements). By making this a constitutional argument, he might get some back-up here because many lawyers love to argue constitutional law as a defense (and many judges love to rule on constitutional cases -- TLC probably knew this was coming, thus the reason for a jury trial)
ITA with all of this.
While that may be true, Heller is arguing that the original contract was not valid. For example, suppose I had a contract with you to purchase illegal drugs. It wouldn't matter how much legal representation each of us had, or how long we had conducted business together, if you suddenly decided you didn't want to supply them I would not be able to sue you for breach of contract, since the courts have already decided that a contract like that is not valid. And that is just a simple situation.
Contracts involving people are even more complex than contracts involving goods, since there are so many existing laws, precedents, and constitutional rights that override any details within a contract.