Once Darl got taken away by the insane asylum people I realized that there have been hints the whole book that he was crazy. In the beginning of the novel when every member in the family called him "odd" and "off". Also, Darl laughed at things that he should not have laughed at. Throughout the entire book, the actions of Darl make sense once you find out that he is considered lazy. For example, lauging at his dead mother's coffin makes him seem very weird but once you discover he is mentally ill, it acts as a reason for his laughing.