Albert Barnes Commentary Esther 10:3

"For Mordecai the Jew was next unto king Ahasuerus, and great among the Jews, and accepted of the multitude of his brethren, seeking the good of his people, and speaking peace to all his seed." — Esther 10:3 (ASV)

Mordecai ... was next unto king Ahasuerus - See Esther 2:5 note. Artabanus (Esther 1:14 note) was favorite toward the end of Xerxes’ reign, that is, in his 20th and 21st years.