It depends. Did your father retire from the military, or did he just serve a term or two? Does he have a Military ID? If not, then sorry- you're out of luck.
I'm ignorant about military terms. I think he still may have a worn, tattered 50-ye old ID from when he was on duty. So if he did a 4-year stint, is he eligible?
He also has to stay with you!! He is the sponsor of the room and he can only get 3 rooms at a time. Also Shades of green is closed they are re doing it.
If you or a member of your family is a federal employee (not a retiree though) of the Department of Defense, they are also eligible to stay and/or purchase tickets from SoG.
Lilly's Dad,
In addition to the ways already mentioned to qualify for staying at SOG, here are a couple more. One is if your Dad earned the Medal of Honor. I believe another is if he was a former POW. You should take a look at the web site. If you still have a question, have your Dad call SOG ressies and ask.