Was your friend Latinx? Just wondering. When I heard my granddaughter's other grandfather (not my partner) call her Mami, I was disturbed and thought it was some kind of perversion. But my daughter corrected me, noting her boyfriend's mom called him that, too, if I remember correctly. (Or was it Papi? I will have to ask her.) But anyway, I guess Mami does not mean "mother of children" to everyone!