Sleeping with Castiel | ASMR Sleep (no talking)

Cas's connection to humanity has grown and he recently learned how to relax fully into sleep. Having experienced this, he now realizes how vulnerable sleep can be for humans. You join him for a nap or a good night's rest, both with the comfort and knowledge that neither of you are alone. He would sense anything in time to keep you safe, and you would have his back--there is nothing more satisfying than falling asleep beside Castiel, sharing a sense of mutual fondness and security. ---and a single phrase uttered in his sleep at some point, what must he be dreaming about?