In The Return, Rumple/Gold ask August who told him about the knife, he said a ‘little fairy’.
I really don’t think Neal/Bae would tell August about the dagger and how to use it.
That was a highly guarded secret….Bae saw the consequences of what happens to someone (Enora) who even possibly had that knowledge.
I mean, yeah, his father let him go, betrayed him and broke their deal, but, I don’t think he would want him dead.
By telling August that info, thare’s always a chance that info could fall on the wrong ears and Rumple could end up dead….or whoever else might have that info could end up dead.
I don’t think August knows who Neal is…if he is Bae (which I think he is).
I don’t think he would want to run the risk of his father knowing where he was…while I don’t think he wants him dead, I don’t think he wants to see him any time soon, either.
Plus, if August had the info as to who/where Bae was, why the ruse with Rumple? Why not just make a deal…..Rumple’s help in exchange for the where abouts of his son…wouldn’t that have been easier?