Who is Al Simpson from The Memory Keeper's Daughter and what is their importance?

Al is a truck driver who sees Caroline Gill in the parking lot of a store on a wintry night. Caroline's battery is dead and she is desperate, with newborn Phoebe in a box. Al invites Caroline to get warm in his truck and figure out what to do. He eventually takes her home and spends the night on her sofa, much the nosy neighbors' delight. When Caroline moves away without telling anyone, Al spends a year trying to track her down. He eventually finds her in Pittsburgh and returns every weekend to spend time with Caroline and Phoebe.