He's going to sue the shit out of Google...
...and win big.
If it's a jury trial he may win but I think he would lose on appeal.
Why lose on appeal?
He is an "at will" employee and the company believed his words hurt the company. He wasn't looking for a legal remedy for what he was saying, it was just an opinion. If he felt what was going on was illegal, he would have tried to correct the situation through the justice system. He didn't, he wrote an opinion piece. From what I've read, he didn't cite any statutes or legal precedent. Besides, they don't really need a reason to fire him other than to say he was no longer needed.
JSA and Danno are the labor lawyers, I'm sure they would know.
Each day is what you make of it so make it the best day possible.