Great-Uncle Bruce
Bruce Heffley wasGreg Heffley's Great-Uncle who was known to have passed away "a few" years prior to the start of "Cabin Fever".
Greg mentions him in an anecdote about the hand-knit blanket Bruce used in the hospital; the blanket had been passed off to Greg after his death. The latter imeadiately ceased to use it after viewing a photograph of Bruce wearing the blanket, and passed it off to his brother Rodrick on his birthday.