First of all, sit down with the Old Gentleman and take down his oral history of his time in the Corps. All too much of that is being lost every day. You can decide what to do with it later on...but find out what happened. He might like that too.
Next, get him a shadow box. You can order them online.
My men gave me a beautiful one when I retired. It is peaked and contains a flag that flew over the capital building in DC, plus my dress medals and decorations, plus a collar device of all my ranks & a small brass plaque of all my duty stations. I would ask your dad if he has any original stuff from his days in the Corps and put them in. If not, just find out where he served and when, what ranks he held and what medals he was awarded. Some are automatic, like the WW II Victory, Pacific Theater, National Defense, etc. You can figure those out fairly easily. Then find out if he got the Purple Heart, or a decoration for valor like the Silver Star or even maybe the Navy Cross...or whatever. Then you just tell the company that makes up the shadow box what to put in there. They should be able to acquire the medals easily and build the box for you.
Take him out to a nice restaurant or have a party at home and present the box to him. Have a camera ready. Don't forget to have the Marine Hymn ready on the stereo and make sure you are ready to assist your dad to his feet when the music starts.
Enjoy!
Here is an example site that sells shadow boxes: [url]http://www.olival.com/home.htm[/url]