On the surface it is, but there are these little cracks and fissures that no one else but them knows about, these small betrayals. Part of it is just growing up, part of it is fear, part of it is fear, part of it is BUTTSEX WITH YOUR BROTHER. HAVE WE LEARNED NOTHING FROM THE WINCHESTERS?? It's a little complicated. It's not that Jimmy doesn't miss his brother, but he's convinced himself that it's better this way, and he wonders if Jacob thinks so too.