The woman does not ask the boy about where he lives or who are his folks. So, what does she do instead and why in "Thank You Ma'am"?

Instead of asking Roger where he lives or about his folks, Mrs. Luella Bates Washington Jones feeds Roger some supper, telling him about her job. After they eat, she gives Roger ten dollars for some blue suede shoes.
As Mrs. Jones walks back to her room at a boarding house after working at a beauty shop that stays open late, a boy tries to grab her purse. But when the strap breaks on the purse, the combination of the weight of the purse and the boy's weight causes him to lose his balance and fall. Seeing him fall

...the large woman simply turned around and kicked him right square in his blue-jeaned sitter.

Then, she picks him up and shakes him. She asks him why he has tried to steal her purse, but the boy lies, “I didn’t aim to.” Mrs. Jones calls this boy a liar, and because he admits that he will run if she releases him, Mrs. Jones tells Roger she will hold onto him. Further, she complains of his face being dirty, so she announces that she will take him home with her to wash it. Mrs. Jones grabs Roger and drags him home. 
While she is fixing a little meal for Roger, Mrs. Jones talks with him, but leaves him alone with her purse. However, Roger "did not trust the woman not to trust him," so he makes sure she can see him. He listens as Mrs. Jones tells him about her job and the customers; she advises Roger to not steal any more. When they finish eating, Mrs. Jones gives Roger ten dollars so he can buy the shoes he wants. Overcome with emotion, Roger only manages a quick "Thank you" before Mrs. Jones closes her door.