Mattis, like most of the board, was there simply for the big money he was being paid to lend the use of his name for the credibility of the fraudulent company. Others included former secretary of state George Shultz (who disowned his own grandson who was one of the main whistleblower employees that brought down theranos), Henry Kissinger, and former U.S. Senators Sam Nunn and Bill Frist, amongst others. All of these were old codgers who still had Washington name recognition and were simply selling their former fame for a price ...
Bill Frist, a medical doctor (surgeon), should have known better.