"Hey, Cas. I can't remember the last time I prayed to you." Dean chuckles bitterly to himself.
"Being human wasn't so easy now, was it? Just kidding, you're great either way, human or angel. I'll meet up with you sooner or later. Me and Sammy are still doing our thing, ridding the world of these demon dickbags."
Uuuh..." He takes a deep breath and continues.
"I'm not sure what to say right now. Sorry? I'm sorry. I failed you and Sammy. He tells me there wasn't anything I could've done but that's a lie, there's a lot I could've done. I won't bother you with 'what ifs' because what's done is done and this time there's no going back."
"I really wish there was, though. You are hearing this, right? Up there in heaven doing whatever it is angels do. Please, don't be mad at me. I- I couldn't abandon Sammy. He's the only family I have. You understand that I can't lose him. If I lose him I'll lose myself. You're my best friend, always will be. And I'll always be sorry for not being there when you needed me most, even though you were always there for me." Dean opens his eyes and draws a deep, shuddering breath to calm himself before closing them again.
"Forgive me." Dean gets up and dusts off his jeans. He glares down at the makeshift grave he and Sam dug up for his best friend. Every time he looks at it he can't help but think Cas deserved better, but this is the most they could do. He stuffs his hands in the pockets of his leather jacket. He continues to look down at the grave for a while as his expression softens and tears begin prick his eyes. He rubs the oncoming tears away with his sleeve and scowls once more before turning around and trudging back to the bunker through the snow. He suddenly stops in his tracks.
"I'm so sorry... Bye, Cas." He whispers in a shaky tone and continues to walk away.