It's his own, but he didn't know it was his daughter when he named it. He just likes children because he thinks he can't have children, so he volunteered to be the nominal father of the children. Aqiao finally told him that Haley was his own, and he didn't understand, so he thought Aqiao just agreed to let him be the father of the child.
Because of Wen. When I was a child in an orphanage, a nun named Haley was always kind to them. He is very grateful, so he wants to commemorate her and hope that the child will be named Haley.