In Chapter 20 of The Catcher in the Rye, Holden sits in Central Park with water freezing on his head and starts to worry that he will catch pneumonia and die. This sets him off on a mental tangent about funerals, cemeteries, and his dead brother Allie:
I hope to hell when I do die somebody has sense enough to just dump me in the river or something. Anything except sticking me in a goddam cemetery. People coming and putting a bunch of flowers on your stomach on Sunday, and all that crap. Who wants flowers when you're dead? Nobody.
All the visitors could get in their cars and turn on their radios and all and then go someplace nice for dinner--everybody except Allie. I couldn't stand it. I know it's only his body and all that's in the cemetery, and his soul's in Heaven and all that crap, but I couldn't stand it anyway. I just wish he wasn't there. You didn't know him. If you'd known him, you'd know what I mean.
(Salinger, The Catcher in the Rye, sleeplessinmumbai.files.wordpress.com)
Holden finds death to be an inevitability, but doesn't really care about the dying itself; instead, like everything else in his life, he focuses on what he perceives to be the dishonesty in others. They will "lay flowers on his stomach" and then "go someplace nice for dinner," the implication being that they don't actually care about remembering the dead but instead are simply making themselves feel better with a meaningless gesture. Death, therefore, is just another thing that the "phonies" will use to show others how much they care, while in reality the death -- even of someone like Allie, who Holden genuinely loves -- means nothing to them.
If there is some level of maturation, or anything resembling, it might be seen in chapter 20 with regards to Holden's thoughts about death. It seems that Holden's feelings and emotions towards death causes him to move, in the smallest of ways, towards the maturation side of the emotional spectrum. It is death that causes him to think beyond himself. His own feeling about the "bullet in the gut" helps him to conceive of his life as something that is less than desirable to live. The image brings to life someone who is "living dead," meaning that their life is one without much in way of meaning and Holden is willing to acknowledge this in his own consciousness. When he contemplates his own funeral, he thinks of his own mother and how she would be when he dies. This is significant because Holden's thoughts about death help to bring about some level of maturation within him, and compel him to think about something outside of his own state of being in the world. Finally, the greatest movement towards maturation in Holden's thinking about death is that he becomes seized with the fear of leaving Phoebe. Holden understands that losing Phoebe would be the worst possible scenario. Out of this fear of death, Holden goes home to see Phoebe. The fear and emotions associated with death compel Holden to return home, and, in the process, help him to embrace a level of maturation unseen at this point in the narrative.
His thoughts nclude a wish that" I almost wished I was dead". He explained it as "this shows Holden is overwelmed by the happenings in his life, and although he should be tired having travelled a long journey from Pencey Prep to New York, his sleep is disturbed. This then leads to further symptoms of depression: misery and feeling alone"