D.B. Caulfield is the eldest son in the family. He has a talent of a writer but has decided to sell his work for Hollywood movies. Holden criticizes D.B. for being a sell-out. However, Holden does respect his brother calling him the best writer. Also, D.B. was taken to the Army and stayed there for four years. On the one hand, this situation gives him themes to write about war. On the other hand, Salinger says that you don't have to go to war to write about it perfectly.
D.B. is a symbolic character who can be analyzed as the opposite to Salinger who didn't allow his book "The Cather in the Rye" to be adapted into a film.