Brothers as foils

[abasil9]

In the pages we have read so far, we are shown through the voice of Jewel that he has a dislike for Cash. Jewel does give good reasons for his rivalry with Cash, including Cash's seemingly subservient nature and a desire to please his mother more than Jewel can. However, Cash's point of view does not mention anything about Jewel at all. These characters are therefore perfect foils for eachother, as Jewel is paranoid about his brother trying to win over their mother, and looking out for his own interests in the process, while Cash is entirely absorbed in the work of building the coffin of his mother. Also, Jewel is shown to be (although internally) passionate and volitile in his emotions, while Cash has hardly shown emotion in the novel at all. Do you feel like faulkner is trying to make a point about rivalry or the relationships of brothers here?
Also, Darl heightens the sentiments of rivalry by juxtaposing Cash's selfless action with that of Jewel's almost self-obsessed behavior. What stake does Darl have in their relationship? Why does he choose to make the reader like Cash and dislike Jewel, other than his obvious preference towards Cash? Why is he so biased in the first place?

[jsipe9]

I feel like Cash and Jewel are slightly parallel to Oedipus and Creon in Oedipus Rex. Oedipus was paranoid about Creon plotting to take the throne, just like Jewel thinks Cash is trying to "win" all of Addie's attentions. At the same time Creon had no desire to take control of the Thebes and was not aware of the rivalry that Oedipus saw. Similarly, Cash is seemingly unaware of the rivalry that Jewel sees.