Commentary for Genesis 35:28

AND THE DAYS OF ISAAC WERE. There is no strict chronological order in the narrative of the Torah. The sale of Joseph preceded Isaac’s death. This is Rashi’s language. Now I have already written²³⁷Above, 11:32. that such is the customary way of Scripture with respect to all generations: it tells of a person and his children and his death and then begins with the account of the next generation even though the generations overlapped.
Now it would have been proper for Scripture to present Isaac’s death prior to the experiences of Jacob, just as it did in the case of Abraham and all former generations. But by this delay, Scripture intended to state that Isaac died in a good old age, an old man, and full of years²³⁸Ibid., 25:8. — [just as is said of Abraham] — after his blessed son Jacob, the inheritor of his high rank, returned to him, and his sons Esau and Jacob, great men of the world, buried him.²³⁹Verse 29 here. It was not necessary for Scripture to mention that they buried him in the cave of Machpelah since it mentioned that Isaac was in the city of Hebron,²⁴⁰Verse 27 here. and where should they bury him if not near the gravesite of his father?

ויהיו ימי יצחק מאת שנה ושמונים שנה, Isaac lived to be one hundred and eighty years old. The reason that the Torah does not add אשר חי, "which he lived," as it did when reporting Abraham's death or Jacob's death or even Joseph's death, may have been that from the day of his birth until the time he was bound on the altar no wife had been assigned to Isaac; our sages in Kohelet Rabbah section 9 state that anyone who lives without a wife is not really considered as "living." On the other hand, our sages also say that as a result of the עקדה Isaac began to lose his eyesight (Bereshit Rabbah 65,10). A person who is deprived of his eyesight cannot be described as truly "alive."

ויהיו ימי יצחק, וגו', “Yitzchok lived to a total of 180 years.” Rashi reminds us that the Torah is not obligated to narrate in chronological order, seeing that the sale of Joseph had preceded the death of Yitzchok. Nachmanides explains that it was an accepted custom when relating someone’s biography, to complete that person’s biography, and only then to begin to describe details of the next generation and the characters that are important during that generation. Actually, the death of Yitzchok should have been reported still earlier, just as the Torah reported the death of Avraham or other generations before proceeding to inform us about the activities of Yitzchok. The reason why the Torah had delayed reporting Yitzchok’s death until now needs explanation. We have to justify the delay displayed by the Torah in reporting Yitzchok‘s death only now as reflecting the Torah’s intent to show us that he lived to a ripe old age, long enough for his son Esau to return to the parental home and take part in the funeral of his father. There was no need to tell us that Yitzchok was buried in the cave of Machpelah, seeing that he lived in Kiryat Arba, right next door to that cave.

Alternatively: since he did not bring חיים with him on his way to the עקדה, the Torah did not see fit to mention the word חיים in his connection.