If we argue that Delia bears some responsibility for her husband's death, it would have to be tempered with the torment she suffered throughout their marriage.
Delia hears her husband's cries when the snake attacks him. She does not offer help to him. Yet, I think that this has to be balanced with the level of emotional pain she experiences. It is clear that Sykes is far from a model husband and human being. He enjoys tormenting her and disrespecting her. Even with this, Delia still shows loyalty towards her husband and their marriage. When she comes home from a Sunday service and is about to start her evening work, hopeful restoration fills Delia's heart:
She went on into the house with a new hope in its birth struggles. Perhaps her threat to go to the white folks had frightened Sykes! Perhaps he was sorry! Fifteen years of misery and suppression had brought Delia to the place where she would hope anything that looked towards a way over or through her wall of inhibitions.
However, when Delia sees the snake in her laundry basket, placed in there by Sykes, it is clear that she can bear this condition no longer.
Hurston creates a "quiet" and "cold, bloody rage" within Delia. Through "a period of introspection, a space of retrospection," Delia grows resigned to her condition when she says, "Well, Ah done de bes' Ah could. If things aint right, Gawd knows taint mah fault."
Delia might have to shoulder some of the blame for Sykes's death because she did not assist him. However, her inaction has to be seen in the context of their entire marriage. It seems that an unfair burden would be placed on Delia if her actions are not viewed in this wider context. This complex and nuanced view is Hurston's direct intention. She wishes to communicate the theme of how intense love can coexist with equally intense destruction, and is substantiated by Delia's reaction to Sykes's calls as he is dying.