What is the point in trying a 91 year old man for a war crime he was said to have committed 70 years ago?

While John Demjanjuk may have do en what they said how could he have ever have gotten a fair trial? None of the people who judged him where ever in the same situation. He was a young man in his early twenties and if he had not done what he ordered he would have been sent off to fight on the eastern front against the russians which is about like getting a death sentence. It is real easy for people to say what they would have done as they sit safely in their armchairs but who knows what choice you might have made if you were in those cirstances.