WW1 Letters

My grandmother left them to me.They are a collection of letters written from a Kansan named Lacey W. Sawyer to a young friend (my grandmother) Fern Clemens Nunemaker also from Kansas during WW1. He was stationed mainly in France. I don't know if they were friends or penpals as so many young people are to our soldiers today. One letter speaks of how they will meet for a picnic when he returns to the states, but I don't think they ever got to go on that picnic because there is an article that says he died after coming home due to experiences of the war. I have alot of other pictures too. Thank you for your expertise.