Tell them you're grateful for the sacrifice they have made. That you're praying for them, that you're proud of them. Let them know they are not forgotten.

Send only a post card, because of security issues they cannot accept letters, packages, or anything other than postcards.

Mail to:

A Wounded Soldier, Airman, Marine, or Sailor
Bethesda Naval Hospital  
8901 Wisconsin Ave, Bethesda, MD 20814

A Wounded Soldier, Airman, Marine, or Sailor
Walter Reed Army Medical Center
6900 Georgia Ave., NW Washington, DC 20307-5001