Near the end of season 1, in particular episode 1x21, Dan doesnt like the fact that Nathan and Lucas are bonding. You can tell by the way he looks at the 2 when they're working out, and even Whitey comes up and says "I bet this is your worst nightmare."
AND.. what made him change his mind all of the sudden? Near the end of that episode, we see Nathan and Lucas running in the gym, by themselves, and Dan walks up and sees them and he seems happy.
So 1, why did dan NOT like them befriending eachother, and 2, what made him change his mind?