The most obvious symptom of the illness that has placed Billy in the hospital is his stutter, which, like the Chief’s fog and Harding’s fluttering hands, grows worse when he is under stress. The stutter forced him out of college and lost him the girl he wanted to marry; interestingly, Billy shares this speech defect, along with an innocence of spirit and a final doom, with another famous Billy of American literature, the title character of Melville’s Billy Budd- the second obvious reference to Melville in the novel. (The first of course is McMurphy’s whale-decorated shorts.)
The stutter, however, is a symptom of a more serious disease: Billy’s inability to grow from a boy into a man. Manhood is defined in this book largely in sexual terms, and the fact that Billy has not lost his virginity though he is past 30 shows that he hasn’t taken command of his life in other ways as well. As he admits, he lacks guts. The reason? He has been dominated by a mother who will not let him grow up (perhaps, it is hinted, because his growing up would be a sign of her own growing old). Definitely a member of Harding’s matriarchy, Mrs. Bibbit has pushed Billy into the hospital; her good friend Nurse Ratched does her best to keep him there.
Just as Billy’s plight is defined sexually, so is his recovery. At first he is embarrassed by McMurphy’s lewd jokes; soon he is flirting with the nurses and making jokes himself. When McMurphy’s prostitute friend, Candy Starr, visits the ward, Billy alone knows how to make her feel at ease with the sort of attention she’s used to: a wolf whistle. And on the fishing trip it’s obvious Billy is more interested in Candy than he is in salmon.
The attempt to achieve a final cure for Billy brings us to the climax of the novel, as McMurphy arranges for him to lose his virginity to Candy. This arrangement ends disastrously. After enjoying a successful night together, Billy and the prostitute are discovered. For a few minutes, McMurphy’s cure seems to have worked. Billy grins fearlessly at Nurse Ratched and wishes her a good morning without stuttering. But in seconds her anger reduces him to a weak “gutless” child again, tongue-tied, begging for her mercy, blaming the situation on everyone but himself. He can’t stand this retreat back to the boy he was before; he commits suicide, as he had twice before threatened to do. His death sends McMurphy into his final, fatal battle with the Nurse.