Parashas Chayei Sarah · Passuk 25:8
And Avraham breathed his last, dying at a good ripe age, old and contented; and he was gathered to his kin.
Rashi on Bereishis 25:9 / Bava Batra 16b (on the good old age) (classical source on this passuk; not listed as a numbered Torah Temimah unit here).
Lemma / focus: בשיבה טובה.
English: From here [we gather] that Yishmael did teshuvah and gave precedence to Yitzchak; that is the “good old age” said of Avraham.
Derash on the verse (Rashi / Bavli) — not a formal named middah of the 13: the phrase “good old age” is linked to the son’s return in repentance.
Avraham’s “good old age” includes Yishmael’s teshuvah and his yielding the lead to Yitzchak at the burial.