I read The Diary of a Young Girl when I was younger than that and it's common to read a certain realistic WWII novel in our schools around that age. I had also read non-fiction about history and different wars even before that and WWII is taught in 8th grade. So unless he is more sensitive than others he should be ok with facts. After all, some boys already served during war, mainly at the home front, when they were only 15 years old because there were not enough men for the army anymore.
After all, some boys already served during war, mainly at the home front, when they were only 15 years old because there were not enough men for the army anymore.