I live just outside Brooklyn, and work in town. This year's graduating class had roughly 40 kids in it- kids that grew up together and many of their parents are friends, siblings are friends. I'm sure he considers Mollie a friend, as she probably does him. Being such a small town (and school) most of the kids are a close group. I overheard one mention that she can't date most of the guys in school because they are like her brothers.
As we all know, life gets in the way, especially if you are a busy young adult- it'd be easy to get caught up with work and family and school, go a month and not speak to someone you were close to all your life.