How about a timeline theme? Like start out with the things that were "in" 80 years ago, and go through today's age. Have music that goes through the time line as well. Start with the 1920's (flappers), 1930's, 40's, 50's, etc. You could have pictures of new inventions through those years, clothing styles, music, food, fads, etc. Each era could be represented briefly. It may take some research and work to bring it all together, but it could be a really nice remembrance for your dad to remember the "good old days".