On the second day after the children were brought to the Lathander farms, Piak would pay them a visit, offering them to show them the ancient elven city if they want to. His intention is to take the fear from the children, after they were no doubt subject to Zhent propaganda for months.
He would show them nice places to swim in the river and to play, and of course the many wonders of the ancient city, the palace, the platforms high above the city, the winged elves and so on.
If the children tell stories of their own time with the Zhentarim, he'd listen carefully, but not dig too deep in the children's memory.