Again, if he violated Apple policies, he can be fired. That’s likely in his employment agreement that he signed. Those policies do not have to be federal crimes.
And again, Apple fired him because he violated a law. When firing somebody for cause you have to be specific, and it has to be fair. A court evaluates this under the principle of good faith.
You cannot fire somebody for mismatched socks, even if you have a policy against it. It is fair to fire somebody for violating a law.
However, if you fire somebody because of insider trading, and a court finds that no insider trading occurred, then you're in trouble because your reason for firing was invalid.
If an employer fired you for theft, and it was proven in a court of law that no theft occurred, what would you think? Do you think that's fair? Do you think you should be compensated? Use common sense.