Well, who’s to say that Hook knew who Baelfire was? Bae may well have kept that secret, even if Hook revealed that he knew Rumple or Milah at some point.
But if Hook does find out, oh, he’ll tell Bae. Won’t be quite as sexy as when he told Belle, but it’ll be just as emotional and just as intended to poison any relationship between the hearer and Rumple.
The way I see the Hook-Henry possibilities is that Hook would only endanger Henry if he knew it would hurt Rumple. However, he could easily (as already happened in Manhattan) put Henry in danger from Rumple due to timing or circumstances of another attack. If Rumple thinks that Henry is endangering his life again, he might lash out and do something to Henry. I still think the chance is remote, but Rumple was perfectly willing to exchange Cora’s life for his and he’s still a coward.
Keeper of Belle's Gold magic, sand dollar, cloaks, purple FTL outfit, spell scroll, library key, copy of Romeo and Juliet, and cry-muffling pillow, Rumple's doll, overcoat, and strength, and The Timeline. My spreadsheet: https://drive.google.com/file/d/0B6r8CySCCWd9R0RUNm4xR3RhMEU/view?usp=sharing