My grandfather served in WW2, not WW1. In his case, he actually lied about his age to join, and also was made to temporarily change the German surname you might

My grandfather served in WW2, not WW1. In his case, he actually lied about his age to join, and also was made to temporarily change the German surname you might notice in my username. He was enlisted for the duration and stayed on for decades after. Only left when they made him (medical).