As Darl confronts his father about the need of hauling the load of lumber and the practicality of securing the three dollars, we realize that Darl has a strong practical side to his nature and furthermore knows how to go about accomplishing such a task. Later, it will be Darl who will be sensible enough to prevent the fight in Jefferson between Jewel and the town man. The reader should take these facts into account when trying to determine the degree of sanity that Darl possesses.
However, one could also view Darl's desire to deliver the lumber as another method of tantalizing Jewel, of taking Jewel away from his dying mother. Darl is certainly aware that Jewel is unable to face any type of reality where his mother is concerned. Jewel refuses to believe that she is dying and even refuses to say the word "coffin." Darl is acute enough to notice this reluctance and explains it by saying that Jewel doesn't know how to express his love and speaks with harshness so as to cover up the fact that he can't say the word coffin.
Since Jewel can express his love only violently, Anse then completely misunderstands him. Anse thinks that Jewel has no love for his mother and no respect for her. But, as Darl points out, it is because Jewel loves her so strongly and so violently that he acts as he does. Darl's perception is further indicated in the manner in which he judges his father. He mentions that once when Anse was young, he was sick "from working in the sun" and now believes that if he ever sweats he will die. But Darl knows that Anse uses this excuse to cover up for his laziness.
