Graham Family is the current name of Graham's family starting with his dynasty.
Though originally of the Cracker family (KQGS), in Daventry Graham is stuck with the subtitle "of Daventry" or "of Llewdor" (or more heroic titles) because locals wouldn't let him get past the first two letters "Cr-".
When his family was reunited, Team Sovereign (Graham's nickname for his family) went by the name "Graham Family" which suggests Graham is their new 'surname'/'family name' Though this is left off their names instead going for fancy titles, or locational titles.
- Valanice (Neese or Vee (KQGS))
- Gart (son of Edgar last name unknown)
- Edgar (last name unknown, but maybe considered part of the Graham Family)
Behind the scenes
Graham's surname being 'Cracker' derives from the original canon from an Easter egg in King's Quest 2, and a reference in Quest For Glory 1. His last name according to the King's Quest II manual, and The King's Quest Companion. The reboot canon makes a reference to it.
According to an older account, several of Graham's relatives have been knights of Daventry, and Graham grew up in Daventry as a child, Graham's father Hereward was a knight and a nobleman, his grandfather (aka Great-Grandfather of Rosella) was a knight (famous for defeating the Dragon of Herenna) and that both were famous knights of Daventry.
According to another account, Graham's family did not stretch back long into the roots of the kingdom (and that he may not have even been a 'noble' either). But regardless may have been distantly related to Edward's royal family. See BB universe.