In WWII Germany was on a total war footing. As a result all men of service age were expected to do their duty. In Germany, the definition of service age was much broader than it was for the United States. Initially, the youngest soldiers in the German Army were 17 or 18 years old. however as the war ground on members of the Hitler Youth were incorporated into the army and most boys 16 and older were serving in the military. Anti Aircraft flak guns were often manned by boys. Beginning in May of 1942, in response to British bombing, all boys 16-18 were required to participate in manditory defense strengthening training (Wehrertüchtigungslager) on the use of Flak Guns as well as all typical combat weapons such as rifles, panzerfausts, etc... By early January of 1943 all Flak guns were officially manned by Hitler Youth boys. On September 25, 1944, the Volkssturm was formed. All males aged between 16 and 60 were drafted into this people's army and trained in small arms with an emphasis on the use of the Panzerfaust. In the waning months of the war boys as young as 10-12 were fighting in combat. "At the Pichelsdorf bridges, 5,000 boys, wearing man-sized uniforms several sizes too big and helmets that flopped around on their heads, stood by with rifles and Panzerfausts, ready to oppose the Russian Army. Within five days of battle, 4,500 had been killed or wounded. In other parts of Berlin, HJ boys met similar fates. Many committed suicide rather than be taken alive by the Russians." The horrors of combat and the war in Germany stretched from old men to boys as active prticipants in killing and being killed. Few Germans were left unscarred by this experience. Most of the living German veterans we meet these days were among these young boys who were forced into this total war.
For more information please see the following link: https://www.historyplace.com/worldwar2/hitleryouth/hj-boy-soldiers.htm