Not so clear cut. You would need to be very careful if you tried to pull this. Look at the facts he explained. The investors are just coming in now, and the founders are saying that the stock agreement depends on the investors' lawyers. That's actually pretty reasonable in a situation where you have a bunch of inexperienced founders getting money from experienced investors. The investors might force the founders to agree to different terms in their own stock agreements as well. It's not at all clear that the founders have breached anything yet. If he was to take the code elsewhere, that act could actually be considered the breach.