I think the regulation states that siblings cannot serve in the same combat unit, not theatre of operations. The original "sibling" reg. was established during WW2 because of the 5 Sullivan brothers who served, and died on the cruiser USS Juneau, when it was sunk by torpedoes during the battle of The Soloman Islands in November of 1942. The US Navy launched a destroyer named The Sullavans in 1995.
wil.