it's illegal to fire someone for joining a union, attempting to join a union, or forming a union.

Alex is probably referring to their settlement offers if they prove their case to the NLRB. But the truth is the penalty will probably be far less... they'll likely just be required to rehire the employee and back pay wages from the date they were fired to the day they're rehired (if they win).

I think OP is referring to a potential settlement. The engineers' case alleges the startup violated the National Labor Relations Act.