User blog comment:JetGatlingGun00/Testing Your One Piece Knowledge/@comment-4004918-20120129210002/@comment-53539-20120129224230

Helmeppo was morgan's son, however, was not working for the Marines or for his father when Luffy first arrives. His pressence on the base is owed to him living off his father's image as a Marine officer in position of power. Helmeppo could do what he wanted and get away with it because of his dad.

Once his father left because the spoilt brat had lived off his fahter's image and now his father was disgraced and went to prison the highlife was over. Helmeppo only joined the Marines because he was forced to.

If he wasn't working for Morgan, then he wasn't Morgan's subordinate...