It seems only the mother was aware of the threat that Esau had issued
Genesis 27:42 NIV
42 When Rebekah was told what her older son Esau had said, she sent for her younger son Jacob and said to him, “Your brother Esau is planning to avenge himself by killing you.
Rebecca only mentions to Isaac how disgusting the canaanite women were and that she feared Jacob might end up marrying one of them
Genesis 27:46 NIV
”46 Then Rebekah said to Isaac, “I’m disgusted with living because of these Hittite women. If Jacob takes a wife from among the women of this land, from Hittite women like these, my life will not be worth living.”
Even when Isaac bids farewell to Jacob he only mentions the issue of the Canaanite womem
Genesis 28:1-2 NIV
1 So Isaac called for Jacob and blessed him. Then he commanded him: “Do not marry a Canaanite woman. 2 Go at once to Paddan Aram,[a] to the house of your mother’s father Bethuel. Take a wife for yourself there, from among the daughters of Laban, your mother’s brother
Was Isaac aware of Esau's threat?