He adopted him as a son
Declared himself his father even though he is not his biological son. Formed a father-son relationship with him.
(Modern Hebrew)
Translation
Expression (Hebrew)
אִמֵּץ לוֹ לְבֵן, אימץ לו לבן
Definition (Hebrew)
הִגְדִּיר עַצְמוֹ כְּאָבִיו לַמְרוֹת שֶׁהוּא אֵינוֹ בְּנוֹ הַבִּיּוֹלוֹגִי. יָצַר אִתּוֹ מַעֲרֶכֶת יְחָסִים שֶׁל אָב וּבֵן.
(הָעִבְרִית הַחֲדָשָׁה)