Holden believes that children are more honest than adults, they can't be phony, they are genuine and sincere in their joy and opinions.

"It is not surprising that Holden's epiphany of happiness at the end of the novel occurs in Central Park. Watching his sister Phoebe riding a carousel, he states: "I was damn near bawling, I felt so damn happy, if you want to know the truth."

Yes, Holden did idolize his little sister, Phoebe, she is the only person in the book that he has any real connection with and communicates with effectively.  Holden respects Phoebe, more than he respects any adults in his life.  Holden really loves his sister, in fact she is the reason that he gives up on the idea of freezing to death in Central Park on the bench.

"Holden is always trying to get to the truth, even if it is sometimes elusive, so this is an important revelation from him. The park evokes his own fond memories of childhood, before his brother Allie's death, and seeing Phoebe circling around in this natural setting seems to bring him a sense of permanency and wholeness."

I thought probably I'd get pneumonia and die.  I started picturing millions of jerks coming to my funeral and all. I started thinking how old Phoebe would feel if I got pneumonia and died.  she'd feel pretty bad if something like that happened.  She likes me a  lot. (Salinger)

When Holden sneaks into his apartment, he longs to see Phoebe, he finds her sleeping in D.B.'s room.  He loves her for her honesty and her open expression of love for him.  He enjoys her childish imagination.  He looks at her school books and smiles when he sees are name scribbled as Phoebe Weatherfield Caulfield.

"That killed me. Her middle name is Josephine, for god's sake, not Weatherfield." (Salinger)

Holden appreciates Phoebe's ability to listen to him, to have a real conversation with him.

"I mean's she's only a little child and all.  But she was listening at least.  If somebody at least listens, its not too bad." (Salinger)