What evidence suggests that the family is poor

We know that Kino and Juana live in a hut, sleep on mats on the floor, and that Coyotito sleeps in a box suspended from the ceiling. None-the-less, we understand how poor the area where they live actually is when we find the doctor will not visit the area, and that he refuses his service based upon the fact that Kino has no money.

The doctor never came to the cluster of brush houses. Why should he, when he had more than he could do to take care of the rich people who lived in the stone and plaster houses of the town.

"Has he any money?" the doctor demanded. "No, they never have any money. I, I alone in the world am supposed to work for nothing- and I am tired of it. See if he has any money!"