Harry Potter and the Deathly Hallows
In Deathly Hallows, Vernon Dursley continues to be his usual red-faced, idiotic self. Though he's heard repeatedly that his nephew is in grave danger, he's still rude to Harry, disinterested in Harry's safety, and refuses to believe that one of Harry's "lot" (that would be Voldemort) might attack him, his wife, and Dudley. Only when Dudley speaks up and says that he wants to accept the Order of the Phoenix's offer of protection does the wizard-hating Vernon agree to the offer and go into hiding. But up until the end, he persists in being completely heartless toward Harry.