If they are going to act like an adult, they will be stopped like an adult.
And on the Hitler Youth thing: they were thrown into the war at the last since Hitler was mobilizing anyone and everyone. And these were, like all, brainwashed. But only more so since you can get a youth more motivated than an adult.
The one thing US soldiers understood was Hitler Youth would fight to the end, and while not necessarily trained well or equiped well, the soldiers learned not to dismiss them.