Dean had never believed in wishes. Well, that wasn't quite true. When he was a little boy, he used to wish on shooting stars. At first, he wished for Mary to come back, for John to be his dad again. When he was a little older, he started to wish for John to find the thing that had taken his Mom away; he wished for a normal life. He got more cynical as he got older, but he didn't stop wishing. Not until the Shtriga; when that had happened, he'd given up. He'd learned that wishing was pointless; all you got was heartache.
Dean had been shocked when he found out that Sam believed in angels. Angels were stories, fairy tales. They were what you prayed to when you had nothing else left. They were a story you told to children; that angels were watching over them. Just after Mary had died, he had clung to that story, because he needed all the comfort he could get. But then he had grown up. He had assumed that Sam had grown up too.
When Dean met Castiel, it was more than a shock. Castiel went against everything Dean had held to be true about the world. In Dean's world, there was random, uncontrollable evil, and you didn't get something for nothing. But then Castiel had walked into his life in a shower of sparks, and Dean had found himself believing in Heaven. It was difficult not to when angels walked the earth.
The first time Dean had prayed, it had been in desperation; because he had nothing else left. Cas had praised him, telling him that it was a sign of faith. He had disagreed. Every time he prayed after that, he told himself that he was only doing it because he knew it would work. Praying for Cas wasn't really praying, because he knew Cas would show up. But then, in Purgatory, Castiel had disappeared, and Dean had started praying for real. At first, it was the same prayer as it had always been, "Castiel, where are you? I need your help," but after a few days, it began to change. He started simply asking where he was. Then it was just "are you okay?" After a few weeks, Dean would just tell Cas what had happened to him that day. After a month, it was simply a promise that Dean would find him. After two months, it was almost force of habit, but Dean found it comforting.
When Dean got out of Purgatory, he stopped praying. Once again, he had learned that there was no point. Cas could no longer hear him. Cas was stuck alone in Purgatory because Dean hadn't been able to hold on tight enough. If he was completely honest, even thinking about Castiel hurt.
When Cas took Samandriel's body back to Heaven, Dean had started to pray again. He prayed every night, wishing and begging for Cas to come back, because he was so desperately afraid of what Cas might do. "I'm afraid I might kill myself," he had said. Dean couldn't get that sentence out of his head, no matter how hard he tried. Instead, he prayed. He wished for Castiel to come back; to be alive. He wished for Castiel.
Dean watched as the angels fell to Earth. He watched the infinite streaks of flame. He wondered which one was Castiel. He wondered if it would be possible to find the place where he fell; to give him some kind of funeral. To say some kind of thank you. Because this time, no matter how hard he wished, Cas wasn't coming back. There would be no mysterious resurrection. There would only be a smoking crater somewhere; a burned, blackened hole in the ground was all that would remain of Castiel, of the angel who had pulled him out of Hell all those years ago. The angel who had become the best friend he had ever had. The angel he had fallen in love with. Dean found himself thinking back to when he was a little boy wishing upon shooting stars. Maybe they had all been falling angels. Maybe there would be no more shooting stars.