I know the version of the angels in the empty is generally pristine and basically so close to alive they just look like they are sleeping rather than actually dead.
Well CAS has always been the exception right? He's always been different, that's how he woke up and escaped the empty, twice.
So what if after he tells Dean he loves him and he allows the empty to take him away saving them all from Billy his vessel goes right back to where it was when he first died.
He's face down in the floor head tipped to the side as his body lays limp, almost peaceful but not quite. And ever presently and constantly for the rest of his death his closed eyes leak tears.
Because that's how he died. Emotional and crying and mourning the idea that he was loosing the man who he had confessed his greatest sin too and would never see again. He wasn't awake nor was he conscious. But even in this state his body grieved and did the only thing it could passively do
And so Castiel in the empty was forever known as the weeping angel
