I haven’t seen the complaint, but I hope he’s suing Obama personally for acting outside his official capacity. In other words, Obama didn’t have the authority to fire him in the manner in which he was fired, and Obama would have to hire a private law firm to defend himself...and would have to pay any settlement out of his own pocket.
Provided Walpin wins, Obama would be guilty of violating Federal law and should be impeached and tossed into jail.