Complex sentence: Sgt. "Buck" Eversole was a platoon leader in Lt. Sheehy's company, and many of Capt. Walker's reflections in the film are those related to Pyle by Eversole.
Split into simpler sentences: Sgt. "Buck" Eversole was a platoon leader in Lt. Sheehy's company and the subject of several Pyle stories. Many of Capt. Walker's reflections in the film are those actually related to Pyle by Eversole.