What happened to the Novak family was always Castiel's biggest regret, he promised Jimmy that his family would be okay and he failed. His involvement was what put the family in danger, leading to demons kidnapping Jimmy's wife and daughter. That moment creating a landslide in Claire's troubled life, he took more from her than he could give back. In the end, Castiel's actions led both Jimmy and Amelia to their demise. However, in their final moments both had accepted their fate with ease because it meant protecting Claire. Deciding that should mean something, Castiel decides to fulfill the promise he made all those years ago and ensure Claire lives the long life her parents wanted for her. NOTE: This is an AU setting where the Winchesters and Castiel take Claire back to the Bunker instead of sending her to Jody's.