According to Notch and the news from ZeniMax Media's legal team, the company already paid the fees needed to their lawyers and have a court ready to hear the case should he keep going on with the project.
The bigger news was regardless of if a case does or doesn't occur, the company already wants Notch to repay them for "damages" and other legal fees they have already spent preparing to sue him.
http://www.giantbomb.com/news/bethes...f-limits/3560/