Keep well clear of politics and stick to the domestic. As for Red Cross parcels. depending on his posting he'll either be eating Burger King until it comes out of his ears or subsisting on disgusting MRE's. Either way, spices - jerk seasoning and the like - chilli sauce, Tabasco and garlic always go down well.
I'd also suggest Marmite and Lee & Perrins, but the USMC might see those as chemical warfare!