Who is Ben from Ecotopia: The Notebooks and Reports of William Weston and what is their importance?

Ben is Marissa's older brother. He is described as surly and anti-American. His intense dislike of Weston is based upon Weston's relationship with his sister. Ben is rude and hostile toward Weston, and he consistenly tries to control his sister. In the end, however, he helps convince Weston to stay.