Answer: The drum symbolize Jody's fear in battle. Later, Jody turned the drum to face up sky which symbolize that he understood General's message.
Explanation:
The drum is an important part of story.
Joby is scared of war as he things he is of no use in the war. He has no weapon except drum to be in the war, which he things is very small weapon to stand in the war.
Later, when general explains Joby, he understands the importance of him being in the war. He gains confidence.
His face turned dignified whether at alert or rest position.
