I would just like to say that we have had the brother line before. We’ve had the family line before (remember Goodbye Stranger?). It’s not new. Dean has never been able to tell anyone that he loves them. What does he say instead? He tells them they’re family because family is the most important thing to Dean Winchester. It’s what he was raised on. Sure, the build up was a little shafted, but there is only one person that can help him to learn to love and open up again, it’s his mother, the only person he’s ever said the L word to. With her back, he can now begin to really heal and reconcile with the event that clogged his emotions in the first place. And that could lead to so many possibilities.