I read about the three Barber brothers perishing on the Oklahoma. Shouldn’t the War Dept had taken the hint about preventing brothers serving on the same ship or same infantry division? Especially what happened to the Sullivans later on the USS Juneau.
IIRC during Vietnam, the Army wouldn’t allow brothers to serve in-country at the same time.
In 1941 that would have been the The Department of the Navy, The Department of War ran the Army.
Even the loss of the Sullivan brothers didnt take place in a vacuum; the officers on the USS Juneau had been warning them about the danger all of them faced being on the same ship.