Plot: Dean died before Cas got to say his feelings.
Castiel's POV
"Dean, I like you. I like you, Dean. Ugh," I paced around as I got frustrated and slumped to the seat. I sat patiently fidgeting my foot waiting for Dean. I was going to tell him about how I fell towards him and ask him what it's all about. Castiel. I herad Dean's pained whisper through prayer. I snapped myself to Dean's location as I turned around to see Dean crawling out of the upside down Impala. Shattered glass evey where and so is Dean's blood on his face. I ran to him, grabbed his hands tight and pulling him out of the car. I knelt down on him putting his bloddy and sweaty head on my lap. I pressed my fingers on his forehead hoping it would heal him, but it didn't. "Dean let me heal you!" I said insisting Dean as tears brimmed my eyes, frightened for Dean's life. "Don't Cas, tell Sammy I love him and he's good. Cas, I should've told you this but I loved you and I'm scared," he said tears falling down. "We gotta get you to the hospital," I said trying to pick him up. "No time," he said gently patting my chest.
"No Dean,"
"Take care of Sammy will you?"
"Dean-,"
"Take care of him promise me you will,"
"I will,"
"I'm scared Cas,"
"Let go," I said crying silently as his eyes started to close. "Goodnight Cas," he whispered with his last breath as he went limp. "Goodnight Dean," I said kissing his forehead and pulling him close to me. I sobbed loudly knowing Dean wasn't in this world anymore, leaving Sam as he is. And leaving me again with me. But I didn't want to be me, I want to be the Castiel Dean loved. I want Dean. I knew I was saving one human and rejecting Heaven but they didn't know. That human was all I have left of family.
