How is Ronnie characterised as a foil to Dickie?

Ronnie is a fourteen-year-old boy.... he thinks like a fourteen-year-old, and he acts like a fourteen-year old. His only concerns revolve around getting on with his life, going to school, and talking to his father about normal experiences. Dickie, on the other hand, is older than Ronnie and attending Oxford. While Ronnie has garnered his father's attention because of his problems, Dickie garners his attention for perceived neglect of his duties.