DEAN INSTANTLY REGRETTED STOPPING MAX FROM MAKING THAT DEAL AND TAKING THE MAGIC. Sam was trying to tell him he did the right thing but Dean wasn’t having it because he knows. HE KNOWS. He’s been right there where Max was standing looking down at the person he loves most and knowing they’re gone. If he finds out what Max did, he’ll be the one person in the world who completely understands why he did it. Not that he’d approve, but he’d totally get it.