Sam could feel as the last wave of grace sparked from Castiel. The youngest Winchester's mind was suddenly dragged into a nostalgic display of hope and passion. The images he saw were all centered around one man. They were not of the dying figure before him, but of the one still fighting to be present for the angel's final breath.

He understood.

The angel was in love with his brother.

"Tell him." Cas croaked as the last bit of grace burned out. "Please."

Then it was silent.

Dean came rushing in a few minutes later, but Cas' grace had already burnt out. The ride back to the bunker was in miserable. It took a day of heavy drinking and solemn acceptance before Sam knew what he must do. He must fulfill his friends dying wish.

Sam spotted Dean on the floor behind the racks outside the dungeon. Arms curled around his knees, Dean held his body close to his chest. Sam was about to approach his brother, but a muffled groan caused him to cower. Dean doesn't open up, not when he's asked to explain his feelings face to face. The younger Winchester slid his long frame to the floor on the other side of the rack. The two brothers were back to back before Sam spoke to the empty space in front of him.

"He did it for you, you know." Sam started.

No, that wasn't right.

"I mean—obviously he did it because of you. Cas, he was always trying to do it right. For you. For me. For humanity. You taught him that…"

Smooth Winchester. Dean already knew that. Cas wanted to make sure Dean knew that—

"He loved you."

Better.

"He died for you, more than once." Sam mumbled. "Cas trusted your judgment. He befriended your little brother, even though I—he considered him to be an abomination. Cas loved you, everybody knew that 'Castiel Angel of the Lord's' first priority was Dean Winchester. It's no question why. Not really."

Sam took a moment to glance over his shoulder. Dean was still hunched over, his face hidden from view. Sam wondered his brother was paying him any attention. He needed conformation that the eldest Winchester was hearing his words. Sam doesn't think he can say...whatever he was planning on saying…again.

"I didn't understand at first."

Honesty is always good.

"I thought that angels needed a leader. They needed God to instruct them. All this time I thought that he had—erm—redirected his loyalty. I thought he took his trust and his need to love God and redirected it towards you. Dean, I was wrong. When his grace—withered away,"

There was a sharp intake of breath from over Sam's shoulder. It was all the confirmation Sam needed that his brother was indeed listening. Man up Winchester, this is it.

"There was this—this wave of energy. It bounced around my head and radiated everything Cas. For the first time, I understood. The last bit of Cas' grace, it showed me his purpose. It showed me the reason Cas was able to take the risk in the first place.

I never thought angels could love the way people do. I wasn't wrong, but I didn't know they love so much more.

For God, they pour everything into their love, no matter the risk to themselves. It may never be acknowledged or returned, but that doesn't stop them from putting in everything they are. It's the only way they know how. I don't think—it don't think he knew it could be different."

A hash scoff came from Dean's direction. Dean cleared his throat before speaking. To Sam's surprise, Dean did not sound weepy or distraught. He sounded pissed.

"I get it Sammy. I introduced Cas to humanity. I forced him to betray his family. I gave him over to fight the good fight. But it's okay right?" Dean asked scathingly. "My assistance allowed him to love humanity. How poetic. It's okay that he's dead, right? So long that he knew—"

"It's not okay, Dean." Sam bit the inside of his lower lip. "It's never going to be okay. But it would be better if he knew that you knew…what I'm trying to tell you."

Sam sighed. Was it really this hard to make a confession of love? It wasn't even his confession for fucks sake.

Maybe Sam had been beating around the bush. Perhaps it would be easier to come out and say it.

"Cas loved you." Sam repeated. "The last bit of Cas' aura? It was you Dean.

It was reuniting in Purgatory. It was silently watching as your human takes time to heal after his brother had fallen into the cage. It was having your chest swell up in pride upon being asked if you are God. It was piecing his body back together after Hell had made a mess of it.

It brought shame too.

It was shame knowing that Naomi had so easily pin pointed your weakness. It was shame that all of heaven knew that you would give it all up for one man. It was shame that an angel would not hesitate to bow to an insignificant human.

Cas knew shame because he didn't just love you.

He was in love with you."

Finally.

"And I'm not talking 'pushing you up against a wall and ravish you' love. I'm talking 'everything I am is for you'."

Wait, back up.

"Though I'm sure he wouldn't have declined the first bit." Sam amended.

It was quiet for a few minutes. Dean obviously wasn't about to comment anytime soon, so Sam engaged him.

"Did you know?" Sam asked quietly.

"No."

"Would have it changed—"

"Nothing." Dean barked. "It would have changed nothing."

"Oh."

Sam had not been sure what answer he had been expecting. He figures he would have known if his brother was in love with the angel, but Dean had surprised him before. His powers of observation mustn't be what he thought they were if Sam was unable to tell that the Cas had been in love with his brother. To Sam's credit though, Dean seemed unaware as well.

The room was silent for a long while before Dean spoke up at last.

"The only think it changes now is how much more this was my fault." Dean whispered.

Sam glanced over his shoulder as rustling came from the other side of their barrier. Dean was getting to his feet and making his way toward the exit. Their conversation was finished.

Dean stopped at the frame of the arch before his final words ripped out.

"I never wanted it. All this time and I had an angels love, Cas' love, and I'll never deserve it. The bastard gave me no choice in the matter. He should have chosen someone else. I owed it to him to be someone else."

And with that, the eldest Winchester made his leave. Sam thought it was for the best. He had passed on his message. Wherever the angel is, Sam hopes that he can find peace in knowing that Dean knew.

For whatever pain, rage, or eventual comfort that brought him, Dean knew.