as someone else already pointed out : in page 3 , the fantasy light-novel is The Familiar of Zero / Zero no Tsukaima . and what kind of normal kid will read a boring heavy-novel with walls of texts and complicated kanji words ?
the real reason why the nephew deletes the photo : he is afraid that the police will ask him : " why do you have a photo of a 7th graded girl in swim-suit ? did you take this picture yourself ? you henta! l0licon ped0 . "
and did she swim in the ocean with her glasses on ?
page 21 : here is my present for your birth-day : my beautiful body . now , "unwrap" your present .
page 23 : yeah , who need a cell-phone when spirits are everywhere and tell oji-san everything . and spirits are never out of service range like cell-phones .