Upon reading chapter 26 of J.D. Salinger's The Catcher in the Rye, we can perceive that there is a slight change in attitude and maturity coming Holden Caulfield's way.
Although the change will not be radical, and may not seem as promising, any improvement to Holden's behavior will prove to be beneficial for him to at least attempt to establish a quality of life.
At the every end, Holden closes his story saying:
[...] D.B. asked me what I thought about all this stuff I just finished telling you about. I didn't know what the hell to say. If you want to know the truth, I don't know what I think about it. I'm sorry I told so many people about it. About all I know is, I sort of miss everybody I told about. [...]. It's funny. Don't ever tell anybody anything. If you do, you start missing everybody.
This is what tells us that, telling his story, has somehow helped Holden to conquer some of the demons within. We also note that, by recalling with some form of positive emotion the names of people from his past (i.e. Stradlacker, Maurice, and Ackley), Holden may actually be in the beginning stages of reconciling with it.
This supports that Holden's stay at the rest home comes during a time when he needs support and peace the most. Teenage angst is a normal part of development. However, Holden's particular emotions seem to have been caused by his environment as well as by his own personal weaknesses. He is a confused and anxious young man who, more than many, would have needed to separate himself from the daily routines that helped create his problems.
Hence, while Holden is showing signs of some progress, he certainly can use all the help that he can in shifting his paradigms of life by separting himself for a while of the environments that cause his distress.
If we focus on the behavior that leads to Holden being put in a rest home in The Catcher in the Rye, the argument in favor of his stay in the rest home is clear. Driven by a depression related to the death of his younger brother, Holden exhibits many signs of psychological weakness.
Holden puts himself at risk on several occasions and demonstrates some self-destructive behavior. Some examples of episodes where Holden puts himself at risk include his goading of Stradlater (to the point that Stradlater punches Holden and knocks him down, drawing blood). Also, Holden challenges the elevator man and pimp at his hotel, refusing to pay an extra five dollars despite a clear threat of physical violence from a man much bigger than he is. Holden is again punched.
More evidence of Holden's fragile emotional state comes in his compulsive opinions. He is incapable of encountering an experience without generating a strong opinion, usually negative. His judgements of the world around him demonstrate the alienation he feels and the resulting sense of isolation.
Holden's hatred of phonies and unwillingness to tolerate them sets him apart.
Holden is not "above" the world he encounters as much as he is disconnected from it, especially from the people who populate it. Until Holden can construct an identity which allows him to be a part of the world he lives in and until he can gain control of his self-destructive tendencies, he ought to stay in the rest home.