Thank you for the question on biblical relationships, “Why was Esau closer to Ishmael than his brother Jacob?”
The Scripture is silent between the relationship of Esau and Ishmael. It is possible that both Esau and Ishmael could have been closer but one has to remember that there is a one generation difference between them. Ishmael would have been considered an uncle.
It appears that Isaac and Ishmael reconciled since both were present at the burial of their father, Abraham. Esau and Jacob were both present when they buried their father Isaac.
Genesis 25 says this, “Abraham lived a hundred and seventy-five years. 8 Then Abraham breathed his last and died at a good old age, an old man and full of years; and he was gathered to his people. 9 His sons Isaac and Ishmael buried him in the cave of Machpelah near Mamre, in the field of Ephron son of Zohar the Hittite, 10 the field Abraham had bought from the Hittites.[a] There Abraham was buried with his wife Sarah” (NIV).
Genesis35 says this, “Isaac lived a hundred and eighty years. 29 Then he breathed his last and died and was gathered to his people, old and full of years. And his sons Esau and Jacob buried him” (NIV).
It appears the brothers Isaac and Ishmael, Esau and Jacob reconciled or at least were friendly at their father’s burial. Ishmael and Esau were both blessed and established people groups.
Both Ishmael and Esau both experienced lack of affirmation from their father while their mothers caused a difficult relationship with their father. One would think that Ishmael would be more understanding of Esau’s circumstances.
It is more likely that Esau’s bitterness toward his brother, Jacob subsided or lessen. It appears that Esau received was able to break free from his brother’s status over him. Esau had his father’s servants, live stocks, and wealth. Jacob earned his wives, live stocks and wealth. Jacob had the spiritual blessings while Esau received the physical properties of his father. With Esau’s 400 men, he could have easily killed Jacob and taken his possessions. He did neither and both lived in separate land location.
The Scripture is silent as to the numbers of contact or family meals with each other. It doesn’t appear that Esau was still angry with his brother. It’s more likely that Esau was closer to Jacob than to his uncle Ishmael.
SUMMARY: Esau may became closer to Jacob since he had Abraham’s physical wealth and didn’t care as much as for the spiritual blessings on Jacob.
For more perspectives:
https://www.quora.com/Why-was-Esau-closer-to-Ishmael-than-his-brother-Jacob