Hello, I've been looking for this fic for some time and it's driving me crazy.

It took place post 5.22. Castiel tore out his grace before Lucifer killed him and was reborn as a human kid. His mom was a junkie and ended up getting killed over drugs. Dean mistook her murder for a hunt and ended up finding Castiel hidden with her stash. He took him in and raised him. Sam shows up eventually, but he's been driven crazy by Lucifer and is hunting fallen angels so that he can use their grace to open the cage.

Is this ringing any bells? I think it might've been a bigbang fic but I couldn't find it when I checked over the j2 and deancasbigbang masterlists.