Local libraries are usually helpful, if he still lived in Hall County during WW1 then try the library. http://www.hall.public.lib.ga.us/http://www.hall.public.lib.ga.us/ Sometime they keep local family histories. They also may have local newspapers on microfilm. You may find a reference to him enlisting or being wounded or on leave. If he married during that time it may reference his military status in his wedding notice.
http://www.hall.public.lib.ga.us/http://www.hall.public.lib.ga.us/ Hall County Library System (Headquarters Branch) 127 Main St. NW Gainesville, Ga. 30501 ph:(770) 532-3311 fx: (770) 532-4305