Who is Hal Applewhite from Surviving the Applewhites and what is their importance?

Hal Applewhite is the reclusive eldest son of Rudolph and Sylvie. In his pursuit of art, Hal has resigned to his bedroom and no one has seen him for months. He only leaves his room at night to steal food when he is relatively sure that the rest of the family is still sleeping. By the end of the novel, he emerges from his bedroom to build the sets for his father's production of The Sound of Music.