I’m still thinking that he landed here, was taken to Neverland for awhile (perhaps as a Lost Boy if not Peter himself) and that’s how he avoided the aging thing. It starts him in a land without magic, and we know Peter traveled from time to time and took people back with him.
He could easily have been visiting our world when the curse was enacted and he couldn’t get back so had to adjust, started aging etc. If this is the case, it may be that the one thing that unites him and his father is Hook (depending on how Neverland is portrayed here, we don’t know yet but typically Peter / Lost Boys have issues with Hook) and then pile on all the Milah drama they may actually have a reason to work together for a bit, regardless of how angry Bae is bound to be with Rumple.
Keeper of Hook's Trenchcoat.