Who is Will Navidson from House of Leaves and what is their importance?

Will Navidson is Tom's twin brother. Unlike Tom, Will has married, had children, and forged an occupation. He is intelligent, tenacious, and a perfectionist. Over the course of the novel, Will calls on his brother to hep him determine the cause of strange doors and hallways that appear in his home from nowhere. The answer is never found.... and Will never stops trying to figure it out.