Why does Anja agree to let Persis take Richieu into hiding after so forcefully rejecting Ilzeckis offer to do so before?

One night Persis, an uncle of Anja's brother-in-law, arrives. He is on the Jewish Council in a nearby town and wants to take Anja's sister Tosha, her husband Wolfe, and their daughter Bibbi to live with him in nearby Zawiercie, where he has some influence and thinks he can keep them safe. He wants to take Richieu with him as well, and Vladek and Anja agree. The parents watch as he takes Richieu away. It is the last time they will ever see him. A short time later, all the children in Srodula are rounded up to be killed, and the parents are glad that they have sent their son away, but the Zawiercie ghetto is liquidated shortly thereafter.