My best guess is he’s technically her half brother: OOP’s mother (daughter of the grandma in question) + OOP’s father’s father = OOP’s bruncle-husband. In turn, this would make Cletus the Fetus OOP’s nephew/niece, aunt/uncle, cousin, and stepchild. We’re wandering into medieval royalty levels of incest here.
My best guess is he’s technically her half brother: OOP’s mother (daughter of the grandma in question) + OOP’s father’s father = OOP’s bruncle-husband. In turn, this would make Cletus the Fetus OOP’s nephew/niece, aunt/uncle, cousin, and stepchild. We’re wandering into medieval royalty levels of incest here.
Why are you sad, my lovely imouto daughter wife?