http://people.com/tv/john-f-kennedys-grandson-jack-schlossberg-blue-bloods/

John “Jack” Schlossberg appeared in the Season 8 finale as Officer Jack Hammer. Schlossberg is the son of JFK's daughter Caroline Kennedy. ALSO: Showrunner Kevin Wade explains the Blue Bloods season finale surprise. (http://ew.com/tv/2018/05/11/blue-bloods-finale-postmortem/)

^^^ I loved how the season ended!

God bless you always!!!

Holly

P.S. I felt for Frank at the end because I believe that he was thinking about how Mary, Joe, and Linda were missing out on what is going happen.