Chapter 9 portrays Scout's extended family as they go to Finch's Landing for the Christmas holidays. This is the only time when Scout gets to see her Uncle Jack, who is Atticus's younger brother, and Aunt Alexandra, their sister. Uncle Jack never got married, but Aunt Alexandra married Jimmy and "produced a son named Henry, who left home as soon as was humanly possible, married and produced Francis" (77). So, Henry is the son of Alexandra and Jimmy and Scout's older cousin. Francis, then, is Scout's second cousin.
Francis calls Aunt Alexandra and Jimmy grandpa and grandma. Scout further explains that "Henry and his wife deposited Francis at his grandparents' every Christmas, then pursued their own pleasures" (77). Therefore, Christmas for Scout and Jem means visiting Aunt Alexandra and Uncle Jimmy, Uncle Jack, and their second cousin Francis. To Atticus, Jimmy is his brother-in-law, Henry is his nephew, and Francis is a great nephew.