Quite the dilemma, but I am aware of similar constraints in getting a flag to Louisiana. Find out the current size of the flag in its present condition (if folded, leave it so). Buy a slightly larger archival storage box (just use a search engine to find one), then send it to the family. You should send with it some wrapping tissue, called Abaca, which is archival. Gaylord stocks it. They should wrap the entire flag in it until they run out of however much they have. It will help prevent sliding. Extra precautions should be to bring a light comforter to wrap the archival box in so it can protect the box from the heat. Store flat if at all possible. Good Luck!