וַיִּקְבְּר֨וּ אֹת֜וֹ יִצְחָ֤ק וְיִשְׁמָעֵאל֙ בָּנָ֔יו אֶל־מְעָרַ֖ת הַמַּכְפֵּלָ֑ה אֶל־שְׂדֵ֞ה עֶפְרֹ֤ן בֶּן־צֹ֙חַר֙ הַֽחִתִּ֔י אֲשֶׁ֖ר עַל־פְּנֵ֥י מַמְרֵֽא׃
און יצחק און יִשמָעֵאל, זײַנע זין, האָבן אים באַגראָבן אין דער הײל פֿון מַכפֵּלָה, אין דעם פֿעלד פֿון עֶפרון דעם זון פֿון צוֹחַר דעם חִתּי, װאָס פֿאַר מַמרֵא;
Rashi
יצחק וישמעאל ISAAC AND ISHMAEL — From this we gather that Ishmael repented of his evil ways (cf.Bava Batra 16b) and yielded the precedence to Isaac. This is what is meant by the “good old age” mentioned in connection with Abraham (Genesis Rabbah 38:12).
Chizkuni
יצחק וישמעאל , “both Yitzchok and Yishmael;” even though Yishmael was the senior son of Avraham, in fact his firstborn, Yitzchok is mentioned first as he was born by Avraham’s principal wife. Yishmael, after all was the son of a slavewoman.
Ramban
AND HIS SONS ISAAC AND ISHMAEL BURIED HIM. In the language of Bereshith Rabbah,18062:6. “Here the son of the handmaid bestowed respect upon the son of the mistress” [since he yielded precedence to Isaac].