Amestris and Xerxes had three sons and two daughters together. The youngest child was Artaxerxes, who was born a few months after the deposition of Vashti, while Xerxes was preparing for war.
Artaxerxes would have been a child during the events that broke up his parents and during Esther’s rule. He was only 17 when Xerxes was assassinated, his two elder sons with him. I found this a little strange. Did the teen really have a hand in the murders? He’s credited with killing his two brothers while the head of the palace guard took care of Xerxes. Was he so politically ambitious that he came up with this . . . or was he, the only child young enough to have not witnessed Amestris’s horrors firsthand, have been so firmly under her thumb that he went along with it to gain the crown?
Regardless, he succeeded Xerxes and reigned for many decades. All historians I could find agreed that he is the Artaxerxes spoken of in the books of Ezra and Nehemiah in the Bible, known for his kindness to and support of the Jews. Due, perhaps, to his fondness for Esther, who he would have known rather well? Sure. Why not. 
(Photo of the tomb thought to belong to Artaxerxes in Naqsh-e Rustam)