. "Mitzi"@en . . "Grandpa's Mother"@en . "Grandpa's father is a fictional character in the Hey Arnold! TV Series."@en . "Unknown"@en . "Unknown"@en . "Grandpa's father"@en . . "Parents: Grandpa's grandfather\n\nGrandparents: Grandpa's Grandfather's father \n\nSpouse: Grandpa's mother\n\nChildren:"@en . "Grandpa's father is a fictional character in the Hey Arnold! TV Series."@en . . "Boarding House Owner"@en . . "Grandpa's father"@en . . . "Phil \n\nGrandchildren: Miles\n\nGreat-great-grandchildren: Arnold\n\nOthers: Gertrude"@en . . "Stella"@en . "Grandpa's father"@en . . .