This moment right here.
Let’s talk about all the folks who claim that Cas left Dean there alone.
Let’s look at this moment right here. Let’s look at what Cas says: Not, “You’re more likely to be ripped to shreds, Dean.” Not, “You’re not getting out.” No, what Cas says is, we are much more likely to be ripped to shreds. We. He’s not going anywhere without Dean, and anyone who thinks so is deluded given what occurred earlier in this story.
Let’s think about the moments before this, before Dick exploded and his death propelled the duo into Purgatory. Just minutes before, Cas stepped in front of Dean when he was threatened by the Big Bad, the Chief Leviathan, the worst monster Dean had arguably ever faced: Cas stepped in front of him to buy Dean time. Then he bought Dean even more time by catching Dick off-guard, tilting his head back and exposing it so that Dean could stab the correct holy relic through him. They killed the Big Bad together, and that landed them - together - in Purgatory.
The night before all this, Dean extended a measure of forgiveness to Castiel for his role in screwing up the world. I mean, if anyone should know about overstepping, it should be a Winchester, right? Those men walk under the curse of damning the world every day while simultaneously attempting to save it. So if anyone could understand what Cas has done, it would be Dean. Moreso Sam, but since Sam is on his own without Cas at the moment, we’ll talk about Dean and Cas.
And what does Cas say? When Dean admits that he’s probably going to die the next day, and his brother with him, Cas says quite simply, “Well I’ll go with you.” He’s saying, not even the surety of my death will prevent me from being there for you the way you just were for me. He’s saying, your friendship is more valuable to me than my life. He’s saying, I agree, I need to fix my mess, and since you’re willing to clean it up after me, how can I stay behind?
How can you think, for one moment, that Cas has left Dean alone?
He hasn’t, not once since he left Heaven for him, and he’s certainly not going to start now.