Here are some key phrases that you might consider using when you write your letter:

... service to our country.

... fighting for our freedom.

... defending our country.

... keeping us safe.

... sacrifice for leaving your job and family.

... placing yourself in harm’s way.
... heroism.
... model for all of us.

... very brave.
... admired by me and my friends.
... a real hero.
... a very unselfish person.
... made our world safer.
... and your family must be very
proud.