Complex sentence: During World War I, he was responsible for the treatment of wounded soldiers at a hospital in Vichy, and after the war became head of medical services at Hôpital de la Charité.
Split into simpler sentences: During World War I, he was responsible for the treatment of wounded soldiers at a hospital in Vichy. Following the end of hostilities, he became head of medical services at the Hôpital de la Charité.