Not loving the premise ("Come enroll at our school and we'll help you find your mother!")
I read it as Captain Ake was responsible for Caleb's mother going missing and Caleb being placed into the position he is on the (Emerald Chain?) mining station. She's been trying to find him for at least a decade, and feels guilty because of that. I'd guess if its taken her a decade to find Caleb, she probably doesn't want to leave him there whilst she goes and finds Mummy Mir - so she takes him with her to the Athena where she can keep an eye on him whilst she does it.