At this time Joby was probably thinking about how he was defenseless compared to everyone else, about how they had a shield of family and he didn't. (p 168, s 6-7)
I don't know man
When will this be over?
The characters actions show he was scared to be at war and that he wasn't aware of his value in the war at the time.
Your the heart of the army!
Joby believes that he's defenseless because has nothing .
Since the soldiers were at war they might of been afraid not knowing if they were going to go home or not. They might of confided in their fellow members to calm their nerves of war. (Gallery walk art section and CLIPT)
Joby changed when the general had a talk with him about how all the men listen to Joby for pace and how he's the heart of the army. (p 171 L142)
The theme might be that no matter the hardships and devastating that come along the way, you need to keep pushing forward to make it through to the other side. (O captain my captain, The Drummer Boy of Shiloh)