In the Catcher in the Rye, the main character, Holden Caulfield is seemingly disturbed over the death of his younger sibling, Allie. The fact that it was a child who died sends out a message of morbidity and finality- no hopes for a heaven or limbo- and it also sends a sad reminder that life, however new, can also be interrupted. Much similarly, Holden's life seemed to be as much interrupted by Allie's death as Allie's life was.
According to Sallinger, death is also a catalyst. It was the determining factor that changed Holden's life and turned it upside down. He is telling us his story from a therapy ward, which points to the fact that the shadow of Allie has not left his psyche.
Death is also seen as a process that carries with it as much complexity and consequence as life itself. Had this tragedy not occurred, the chain of events in Holden's life would have been very different: Holden would have had a shot at fitting in, and his ambitions would have been different. He might have even had a very different perception of life, and a more peaceful interaction with his peers.
The torment of Allie's death from leukemia has perhaps left Holden feeling as if life is not under our control- it can be taken at any moment's notice. Therefore, his reaction to life became a constant blame game where he assigns responsibility about himself and others on everything that is not our own human will.
Holden suffers deeply from survivor's guilt. He laments his brother Allie's death, saying it should have been him to have died instead. Much of the novel is a rant against being left alone in a phony, materialistic adult world. In other words, Salinger uses Holden's narration to comment on the death of innocence.
The other death that deeply bothers Holden is James Castle's. James Castle was a martyr who fell to his death rather than take back “conceited.” Holden romanticizes his death and reveres him as a saint, like Mercutio and the nuns--those who martyr themselves or the good life for a noble or humble cause. Holden seems to think that it is better to die young than to become an adult materialist like his parents, brother, and nearly every adult he meets.
He seems to be headed toward a similar suicide until he meets Mr. Antolini. He is a former teacher who found Castle’s body and shielded it from rubber-necks. He is a catcher in the rye, the voice of Salinger--Mr. counter-culture.
Antolini's advice to Holden's is Salinger's advice to us. He says Holden is “in for a terrible fall”:
"The mark of the immature man is that he wants to die nobly for a cause, while the mark of the mature man is that he wants to live humbly for one."
Holden doesn't yet know what his cause in life is. I think it's the book, his confession about the pain his brother's death has caused him. So, in the end, the book saves Holden from suicide. The book itself is the catcher in the rye.
As we read the book we can tell Holden sees death as a way to escape, and that he wishes to die. He mentioned the fact that he was glad they invented the atomic bomb, and that if there were ever another war, he wanted to sit on top of it, and that he would even go as far as volunteer. He also mentions the fact that he had wanted to commit suicide before, but the idea of all the phonies in his school looking down at him stopped him. Despite having such thoughts, the whole idea of death is flipped around once Holden goes to the museum, there we learn he really doesn’t want to die, he wants to freeze time and leave it exactly as it is at the moment, he wishes time would no longer pass and that just as the figurines in the glass cases he wishes nothing would change, this could also be read as him wishing not to grow up.