Step-mom here! He would have only been 4 when she married Nico and she was only 18... so very young herself. But she was very involved in her younger siblings growing up so i can see her having always loved him like he was her own. She and Nico run a pretty tight ship... well, he runs the ship and she supports and enforces his decisions. And I can definitely see their being a period or still to this day that Nico's first son would sort of resent her or dislike her, so I'm totally open to rolling with that too! But she would have always done her best to include him and be kind.