Just a couple of thoughts, Snoangel:
1. I would suggest getting direct communication with
@Richard here on we sleuths. He really does seem to be an expert on missing persons cases.
2. Get in touch with the high school to see if they have the reunion team set up for the class of 75. Seriously, these people get into the roll they play, to rally the troops. You tell your story so well....they will help you get the story out there. People who served in those years, were still treated poorly at home, so if ANYONE who communicated with him knows more.
3. Keep posting...even when nothing new is being presented or asked. When people here on websleuths keep seeing new posts they get more interested. So new people keep popping in to learn more. You are so very good at continually responding to all these inquiries. But this is such a difficult search, given the extraordinary connections in military/government records. So most of us have to give up helping. But eventually, the right connections will fall into place.
4. Treat yourself well. You are doing an amazing job, and you will find truth.