muslim girl converted Hindu converted again in Muslim and know giving divorce on the same ground

A muslim girl married with a Hindu boy, after 12years of marriage gave a false complaint to police station of harassement and got converted herself  to Muslim, and know seeking for divorce in court on grounds of harassement and automatic null and void marriage due to conversion is the reason. want to file reply to the filling in court so what grounds should be taken along and which shall benefit the boy who do not want to give divorce and couple have a baby girl of 12years please suggest