[onion2k]

His share of the new company is likely to be worthless if his input would have made the company a success (assuming he wouldn't carry on working on it, and it would be really weird if he did.)

So this is really only about sending a message to other employees.

[LatteLazy]

Unless his input has already been (mostly) completed? If his contribution was organising, introducing people and getting things setup and running then he can leave and the company will roll along just fine?