What evidence from the text supports the idea that shadrack has experienced post traumatic stress disorder, or other mental impacts, as a result of the war?

I believe the answer is: He's constantly having nightmare on his sleep and constantly do a violent outburst as if someone is trying to hurt him.

All of those signs point to a post traumatic stress disorder. This could only happen if in his personal mind, he still believed that he is on a battlefield, even if now he is currently at home. The horrible experience that he face on the battlefield still haunting his mind .