Good point; from https://news.ycombinator.com/item?id=5629255, if the sued employee is even vaguely telling the truth, unless Norwegian trade secret law is vastly different from US they don't vaguely have a case.

Then again, the cheapest way for him to win this battle is in the public arena; without the particulars of their complaint, which we'll hopefully soon learn about, it's hard to say.

But I can say it's never a good sign when a company starts to compete in the courtrooms.