How do the wife and the son contribute to the destruction of the fairytale?
Ah, a sad question. The narrator's wife contributes to the destruction of the fairy tale in several ways. First, she is hyper-rational; she seeks to explain everything, rather than buying into the dream. Second, and probably more important, she isn't the narrator's true love. They're married, but she's no Buttercup for him. That's just sad. Third, she seems to take the son's side.
As for the son, he doesn't fight through the excess words to connect to his dad, or seem to value the book his dad about killed himself getting. He should be able to feel the connection, just as the narrator felt it with his father. He doesn't, and that makes the whole thing hollow.