The piece starts playing on 10:05-10:50 in War & Remembrance Part VIII (YouTube reference). It is just beautiful... but can't overcome the horrors of the place.
What is this song?
String Quartet in F Major: II. Andante cantabile "Serenade" (Formerly Attributed to Joseph Haydn as Op. 3 No. 5, Hob. III:17) I Musici di Zagreb Buy from Amazon