Okay so... this sequence of scenes points out something heartbreaking...
This is the first one:
Dean had to bury him, not them, only Dean.
After that scene ends we can see Dean here:
Praying to Cas, kneeling on the ground, crying, forgiving and asking for forgiveness... And after he wipes out his tears and keeps going this scene comes right after...
Dean is alone, drinking with his eyes closed, focused and with that expression....
He is praying to Cas who's alone, scared and trapped, buried into the Mal'ak box.
Even when Sam comes into the scene, it feels awkward, like he just walked into a very private moment.
So yes, these three scenes are a sequence, one after the other, so we can almost guess is fully intentional. This episode was so so heavy on Destiel, I can't help to hope they'll go all the way canon.
non-reciprocated, my ass.