Another Catholic answer is that "brothers" in Mediterranean cultures could mean cousins and close relatives of similar age, and not just immediate brothers.
Jibu lingine la kanisa Katoliki ni kuwa kwenye jamii za Kimediteranian neno "ndugu" linaweza kumaanisha binamu na ndugu/jamaa wa karibu wenye unri unaofanana, na sit tu kaka au wadogo wa mtu.