Grunkle Stan
Stan is an older man , and the great-uncle ( or "grunkle" ) of the show's main two protagonists , Dipper and Mabel; the show takes place as they stay at his house/tourist trap during the summertime . 
<triplet> Dipper <subj> Mabel <obj> sibling <triplet> Mabel <subj> Dipper <obj> sibling