The military is very quick...
The military is very quick to refer to comrades in arms as brothers. Band of Brothers, the mini-series put out by HBO and produced by Tom Hanks and Steven Spielberg, tells the story of Easy Company of the 101st Airborne in WWII. They trained together in the United States, they parachuted into Normandy on D-Day, and they fought in the Battle of the Bulge. Because of the deep bonding that occurred between them, as they saw members of their company fall to enemy fire, still they had the courage to hold ground in Bastogne and turn the tide of the war.