If he is still active duty, he can get ticket vouchers in advance at his base ticket office. He can also go to Shades of Green resort, which is on Disney property near the Polynesian Resort but owned by the Armed Forces. There is a ticket office there. Also, check on the Disboards home page - I want to say that the "news" square up at the top (where right now it has links to Easter dining information) had a blurb last week about buying miiltary tickets online. Scroll down that box and look.
Hope this helps!