Well, Dean is smol and captured, and Stan is tol, and there was a woman who captured Dean and has experience doing such things… but beyond that I’m not sure what to make of the AU for afin, especially since you said it’s very different than previous AUs. Has Dean been a little his whole life this time?

Dean has not been a little all his life. Though you might see other characters in the stories swap between borrower-for-life and curse-victim, the Winchesters need their past as humans to really be Winchesters, at least for me.
Dean is smol and captured. The woman didn’t capture him.
Stan is Stan.