"Dean- I'm so sorry. I can't do anything." Castiel stared at the hunter, his blue eyes filling with tears, "I can't help Sam. Dean, I-"
"Cas, It's okay. It's fine-" Dean's voice broke, "I just wish there was something I could do. I can't let him die, Cas. He's... he's the only family I have."
'It isn't your fault."
"Yes it is. I could have done those goddamn trials, and he wouldn't be dying. Don't you get it, Cas? I'm his brother. I'm supposed to protect him, and I didn't do my fucking job. Sam is dying because of me."
Dean broke down, his body heaving with sobs. "I don't know what to do, Cas. I don't know..."
Castiel went to him, putting a hand on the hunter's face, something he knew Dean found comforting.
"Dean, listen to me. It's not your fault that Sam took on the trials. That was his own choice. You couldn't have stopp-"
"I could have, Cas. I could have been a good-"
"Stop it. Because of you, your brother is not dead. You stopped him when it most counted. I may not be able to help in the way you want me to, but I can still help. Dean, what do you need me-" Dean pulled Castiel forward into a tight hug, sobbing into the fallen angel's shoulder.
"Castiel," he murmured, "I need you."
"I need you," Dean repeated over and over, clutching Castiel tighter with each word. "Please," he asked, his green eyes beseeching, "please, Cas. I need you."
Castiel pressed an urgent kiss to Dean's mouth, gripping him tighter.
"Cas, I'm so sorry for everything I've done."
Cas gave him a small half smile, keeping his hands on Dean's face.
"I wish there was something I could do. You have no idea. To watch you suffer... Dean, neither of you deserve this. This pain is too much for you to bear. If I could do anything, it would be to help Sam. I know he means everything to you. I know you would give anything to be in his place so he won't suffer anymore."
"I can't watch him go through this anymore, Castiel. He's my baby brother, and I can't do anything to help him. What do I do? I can't..." Dean inhaled sharply, fighting to stay calm. "How am I supposed to sit here every day and night knowing that no matter what I do, it won't help? My brother is dying, and I can't do anything to stop it. I know you keep saying that it isn't my fault, but it is. You know, I should have just stopped him before he started. None of this would have happened."
"You're too hard on yourself, Dean. This was Sam's choice."
"No. You don't get it. I'm responsible for him. I've been responsible for him for as long as I can remember. And if I let him die-" He stopped, wiping a hand across his face. Dean fell into Cas again, the ex-angel holding him tightly."
"It's unbearable- to watch your family suffer. To watch them hurt. To be unable to do anything to help. I would give anything to be in your place, Dean. If you never had to suffer again, it still wouldn't be enough. You've been through so much. Please, if there's anything I can do-"
"Stay," Dean said, his voice thick with sorrow, "Just stay here with me. I need you here, Castiel. I can't do this by myself."