I truly didn't know anyone serving but I searched the net and found NUMEROUS support programs. A "plug" for the one I've used the most for the past 3 years to send letters and packages: "www.anysoldier.com". (The site supports ALL the branches. Just substitute 'soldier' for another branch; for example, "www.anymarine.com".) Individual service people post information about what they need; the site has info on what to send and HOW to send it.
But most important, as stated above, are letters. LETTERS COST ONLY 39 CENTS AND 10 MINUTES OF YOUR TIME! JUST DO IT!
Regards