Charles Ellicott Commentary Genesis 25:9

"And Isaac and Ishmael his sons buried him in the cave of Machpelah, in the field of Ephron the son of Zohar the Hittite, which is before Mamre." — Genesis 25:9 (ASV)

His sons Isaac and Ishmael. —Isaac was now seventy-five years of age, and Ishmael eighty-nine, and the two old men, with their enmity long over, met as friends at their father’s burial. While Keturah’s sons were apparently sent far away into Arabia, Ishmael at Paran (Genesis 21:21) would be at no very great distance from the well Lahai-roi, which was Isaac’s favourite residence.