Letter from German guard to British former prisoner

Edward Joseph Murray was born in 1895 and volunteered for service in 1915. He joined the Cameron Highland Regiment. The family do not know much about his time in the army, but it is believed he was involved in the battles of Passchendaele, Somme and Loos and that he was a stretcher bearer at some point. Towards the end of the war, some time in 1918, Murray was taken prisoner and spent the rest of the war in a German prisoner of war camp, possibly in the Wurtenburg area. After the war he returned to Endinburgh and resumed his work in the civil service. He married in the late 1920s. His son (the father of the contributor) was born in 1934 and was never told much about his father's time in the army. In 1920, Murray corresponded with a German man, Oskar R. Schülz who is belived to be a guard in the POW camp. In a letter from 19th September 1920. Schülz asks about Murray's life after the war, and describes his own situation. Reference is made to an earlier letter from the sender and also to a letter by Murray, which suggests that this was not the first contact. The family do not know how or why the correspondence started but do not think the two men ever met after the war.