Husbands prior children's last name???

Jessie Rae • Owner of 2 gorgeous Siberian huskys☺️ have the best SO I could ask for and TTC #1
My SO and I have finally came to a agreement on our last name issue.
He will be changing his last name to mine. Now as for his kids, who are from a prior marriage, have his maiden last name. 
Could she change their last names to her maiden name or future married name in court because he changed his last name  ?!??