Adopted Season born... humans that are More like Kidnapped, Stolen, abducted or otherwise sworn into loyalty service or worse.  That or saved from the wilds as a child.

Though, and this is from an optimistic point of view,  a Fae, with a Human Friend, who dies, can adopt that child, if that child has nowhere to go. Most Season Born children who are human, are given away to fae who want children to control the amount of season born that could cause trouble. (OR at least, that's what would make the most sense)