Say Goodbye – Hello, Astronaut
Cas was Dean's everything. Next to Sam, of course. They bother were his everything. So whenever Cas would disappear for months on end, without even a word to either of the brothers, Dean would be on edge.
He'd burry himself in his work and practically drown himself in alcohol in hopes to survive. He would fight for Sammy, and he'd fight for Cas, even thought he wasn't with him.
Sometimes, it scared Dean to think that Cas would leave him.
But deep down he knew the angel wouldn't.
Cas would never say good bye.
Not to them.
Not to Dean.
At least he hoped so.