Matenro is my dad

Susumu witnessed a housewife, a regular customer of her parents' greengrocer, shoplifting from the store. Susumu tells his father about this, but his father refuses to criticize the housewife's actions. Why is his father silent when his important items are stolen? Susumu, who is not satisfied with this, fasts to show his resistance to his father. However, when he came home one day, something strange happened to his father!?