Hi Julia!
Walt Disney World is a great place to celebrate a birthday. I'm just sorry to hear that your husband will be unable to join. Please give him my thanks for serving our country and protecting our freedom!
All you need is a military dependent ID card to qualify for the military
specials. Be sure to consider getting the Walt Disney World Resort Salutes the U.S. Military with a 4-Day Ticket; that's an incredible price and you can the Water Park Fun & More and Park Hopper options for half of the normal price!
Also, have you looked into the Shades of Green resort? It's an Armed
Forces Recreation Center in the heart of Disney World. Their website is
www.shadesofgreen.org. Active duty, retired military, and 100% disabled
veterans (and a few others -- see their website) can stay at this
beautiful resort that is right across the street from the Polynesian
Resort. There are several places to eat there and based on my
experience, it's much cheaper to eat there in general than at other
places in Walt Disney World. Lodging at the Shades of Green will be based on your husband's rank, so you would have to do the math to determine what is the better choice.
Enjoy planning and write back if you have any more questions!