Ask HN: What could happen if you accidentally leak your company's source code?

One of my colleagues has accidentally shared the source code of the project of one client for a few days on his personal Github. This project is worth several millions. When our company noticed, they dismissed him.

Does anybody know what can happen to him now?

Do you know if the customer sues our company, our company might sue him?

This has been a mistake, our company knows, and the client knows too, but I feel really worried for him.

Has anybody had any experiences with these kind of situations? Should he search for a lawyer?