In "The Beans and Rice Chronicles," how does the relationship between Isaiah and his mother erupt?

Isaiah grows increasingly frustrated with his mother over the course of the story. She is obviously depressed over Isaiah's father's death, but she seems unable to get out of bed, to do anything to take care of her children. Isaiah is left to take care of his sister, Charlie, and seems to grow more and more resentful. He notes at one point that if his father knew what their life would be like without him he never would have died. When they lose their apartment and move into a motel, Isaiah is only more frustrated, noting, for instance, that it is really his mother's fault he got detention. Finally, one evening he tells his mother he is tired of eating rice and beans all the time. She tells him he can eat what he wants when he has a job of his own, and he asks her pointedly when she is going to get a job. She slaps him, and he leaves, heading for the library.