Everybody's family is different, and never is that more apparent than in young-adult fiction. Usually one or both parents are dead, older siblings have run away, or the protagonist has to play parent to a younger brother or sister. Well, not in The Perks of Being a Wallflower.
On the surface, Charlie's family meets the textbook standard criteria for normal: mother, father, three kids. We wouldn't be surprised if they had a white picket fence. But just because they fit a mold set by 50s-era sitcoms, that doesn't mean they are one big happy family. They definitely have their share of problems, some of them dating back a generation or two. And they're certainly not forthcoming with loving comments and physical affection. Still, in the clutch, they all come together to support each other.