What does the boy learn about the details of another boy's father's arrest that is more disturbing than his own father's arrest?

The boy, troubled by the memory of his father being taken away in his bathrobe and slippers, talks to other boys about the way their fathers were treated at the time of their arrest. The only boy whose father had been arrested in a more disturbing way than his own was wearing way he finds more disturbing than his own father's geta, which are traditional wooden Japanese footwear.