How did Zhu Huan Gege Wei Zi become Gege?

It's almost the last episode of the first movie. Brother Wu went to rob the prison (the last episode of the last episode) and wanted to travel around the world with the swallows, but Ertai thought that Amanu was still ready to go back and face all this alone. Swallows decided to go back and face it together, because they felt it was unfair to let E Ertai bear all this for them. In the last episode, the emperor accepted their absurd story, and Wei Zi fainted at that time, which aroused the nature between father and daughter, so he recognized his daughter.