At one point Richard says something about some "Boys who stayed on to play 'Last Retreat.'" What's referring to when he says this?
Formerly rose-lisa
My name's Andy
Do you hear the people sing, singing the song of angry men?
Young boys would sign on as drummer for the infantry in wars from the 18th - 19th centuries. They were often too young to fight and would learn to drum which was a very important job. Drums were used like trumpets were later on to signal various orders to the troops (like the last retreat), keep the soldiers marching together and boost morale. But also and more horrific would be that these young boys and other musicians like bag-pipe players in the British army would be at the front of the regiment leading the men into battle and in some armies they be right in the front where they would catch a hail of bullets.
The boys were often poor children or orphans. They were not usually paid to drum and often did other chores for the army.
Anthony Quinn portrays the frontline march that musicians would suffer in "The Buccanear" which he directed for his then father-in-law C.B. DeMille. The battle of New Orleans shows the bag-pipers and drummers walking into the battle and being gunned down one at a time.
For a young drummer to stay on for last retreat meant that they stayed in the thick of the battle with no weapons waiting for the final orders to play and hopefully not get killed. This was Mr. Sturges's way of comparing the tremendous bravery that he felt Norman showed; which filled him with both deep love for Norman's bravery and devotion as a son and also anger at Norman for basically giving up his only chance for life to spend his last moments with his father.
Kind of like Gavroche in Les Miz.