The Judgment of Eve by May Sinclair

A year passed. It was winter again, and the Gattys had had sickness in their house. Aggie had been ailing ever since the birth of the baby that had succeeded Emmy. And one evening the doctor had to be summoned for little Willie, who had croup. Willie, not four years old, was the last baby but three. Yes, he was only a baby himself; Aggie realized it with anguish, as she undressed him and he lay convulsed on her lap. He was only a baby; and she had left him to run about with Arty and Catty as if he were a big boy. She should have taken more care of Willie.

But the gods took care of Willie, and he was better before the doctor could arrive; and Aggie got all the credit of his cure.