When the boy had turned up and her doorstep, with the letter explaining to her that her only sister was dead and her only remaining blood relative was now the young child, Petunia had felt something similar to satisfaction, that though her sister had been special it was in fact that specialness that got her killed in the end yet she also felt a grave sense of fear that if the boy was anything like his freakish parents then the same fate that befell her sister and her unnatural husband could befall her upstanding natural family and she could not allow that to happen. This bitterness towards her sister, this fear for her family and the satisfaction of finally being able to treat the freakishness the way she wished her parents had treated Lilly's unnaturalness was an explanation for her utter hatred for her young nephew but as much as Petunia believed it was, it was not an excuse for the way he had been treated by her and the way she had allowed Vernon to treat the boy the way he did.