Side note: We're dubbing this surgical trio "Jolexona." Get used to it.
That boy (played by relative newcomer Gabriel Bateman) and his mother (comedian Lisa Joffrey) are involved with a case of the week, apparently. We just hope that he's not the patient of Arizona's referenced in ABC's official synopsis of Episode 15:
patients on a potential double amputation. Derek [Patrick Dempsey] goes back on a promise to Callie, and Jo and Stephanie [Jerrika Hinton] find an abandoned baby outside the hospital. Meanwhile, the doctors deal with the repercussions of the non-fraternization rule, which include meetings with HR and one doctor's suspension.