Who is Bill Halverson from Canyons and what is their importance?

Bill Halverson is the boyfriend of Brennan's mother. Bill is a churchgoer and he runs a youth group through his church. Shortly after meeting Brennan's mother, Bill invites Brennan and his mother on a camping trip with the youth group. This trip is in the canyons outside El Paso where Brennan finds Coyote Runs' skull.