Step mom was charged with Battery-Family Violence Act can the Minor in the case drop charges
Neither minors nor adults can drop criminal charges, period. Once there is a case, only two people can end it - the DA/solicitor who decides whether to pursue it, and the judge or jury who hears the case and decides it. The injured party is solely a witness (and can be forced to testify under penalty of jail).
No minor can drop charges. See website: http://www.lawrencelewispc.com/pages.php?go=pinfo&PID=363
Good luck