T.K.
Try to stay away from the all black over the hill, graveyard stuff. It's already really daunting having kids at 40 - I know because I have 2. I don't want anyone pointing out how over the hill I am. Maybe it's differant for men. Why not go for a This is your Life theme? Play music from his birth year. What's that 1971? Print newspaper clippings of the big headlines from his birth year. What famous people were born that year. Play trivia from that year on the pop culture of the day. You could find out what were the popular party foods - deviled eggs and stuffed celery were big back then. Or you could just go full on 70s Disco party and ask everyone to come dressed for the 70s.