And I disagree. Sam and Dean don't talk to each other anymore. They don't support each other except in dire emergencies. Dean was swimming in the bottom of a bottle for most of the season and Sam was supposedly battling Lucifer-- not that we ever saw that-- no, he's fine! How many times have we heard that they could be any two random hunters driving around in a car together? There needs to be something that unites them, that they both have to fight against together.