Isabel, the narrator's wife, is important to the story because she has been so much a part of Sonny's life. She both loves him and hurts him, showing the complexity of interacting with hm.
We learn that Sonny lived with Isabel and her family before Isabel married the narrator. While Isabel and her family are kind to Sonny and wish him well, it is clear that neither she nor they understand him any more than the narrator does at first. Sonny teaches himself to play the piano at Isabel's house, but it often seems to the family that he is lost in his own world:
Isabel finally confessed that it wasn't like living with a person at all, it was like living with sound. And the sound didn't make any sense to her, didn't make any sense to any of them- naturally. They began, in a way, to be afflicted...
(The entire section contains 459 words.)