every mother's son of them
Everyone in a particular group. The phrase is not only used to apply to men. I don't know how many people live in this city, but every mother's son of them was riding the subway with me this morning!
every mother's son (of them)
Fig. every one of them. The scout leader said that unless the scouts told him who had stolen the money, he would punish every mother's son of them. When the football team won the championship, they were all crying, every mother's son of them.