לאחיו. הֵם בָּנָיו שֶׁהָיוּ לוֹ אַחִים, נִגָּשִׁים אֵלָיו לְצָרָה וּלְמִלְחָמָה (בראשית רבה):

לאחיו UNTO HIS BRETHREN — really his sons, who were like brothers to him since they were standing by him in trouble and in battle (Genesis Rabbah 74:13).