Dean and Castiel - A Life of Regrets (AU Prompt/Song Request)

AU prompt and song requested by: Terrible Things "I'd like to request a dark Au where Castiel dies leaving a suicidal Dean to raise their three kids (Claire, Jack, and Ben) to this song:    • A Life of Regrets (An Original Chester See...  " Hey Guys, I'll add more to this description when I wake up it's 4:12am here, I should be snoozing. I apologise if there are audio issues, I have an ear infection at the moments so I am avoiding using my earphones, and also everything is slightly muffled.