I never actually read this one but I saw the summary and I’ve been thinking about it a lot lately and I can’t find it. So Castiel wants to help Dean and Sam have a better childhood and in this fic Dean, and maybe also Sam, is a hooker, prostitute, sex worker, whatever the name is. Castiel goes back in time and gets their services but overpays by a lot and maybe gets them food, too? Anyway, Sam and Dean start to really look forward to Castiel’s visits. That’s all I can pull from memory.