John F. Kennedy's grandson Jack Schlossberg is revealing the last thing his sister Tatiana Schlossberg said to him before she died at the age of 35. "I can tell you that she's still rooting for us and the last thing she said to me was, 'You better win," Jack, who announced his candidacy for the Democratic primary in New York's 12th Congressional District one month before his sister's death, told CBS Sunday Morning's Mo Rocca in an interview shared on Sunday, March 1. "No one knew me better and I knew no one better than her," Jack continued.