Why does the professor arrange for Anya, Meredith, and Nina to go to Stacey’s house in the novel, Winter Garden?

The professor arranges for Anya, Meredith, and Nina to go to Stacey’s house because he believes that Stacey is Anya, the daughter who Anya (Vera) believes was killed in a bomb blast. Anya is shocked to see the wedding photo that she put in Sasha’s pocket when he left for war displayed on a table in Stacey’s house. When Stacey realizes that Anya is her mother, she gives her back the butterfly that Anya (Vera) gave her daughter when she put her on the train to meet her father in Vologda.