Hi and welcome,,
I really don't have any expertise , medical or military,, but I think the suggestion to contact HEI is a very good start. I also agree that you should be able to get cd of latest MRI test without waiting for "all" the other medical records,, hospital or imaging center should burn that for you,, of course you will have to take your Dad I am sure to sign consent form on the spot,,,
Do you have a university medical school close to you that may be willing to listen to your story,, maybe they would be able to give some advice,,, may be that he will have to pay for doctor visit with someone to at least get another opinion,, especially if he can get that cd,,, seems VA is " writing" him off and that is very unfortunate for anyone,but especially a veteran!
Maybe local health dept.would have some type of program he would qualify for,, or contact local TV station and tell them of the injustice here,,, what a shame he has been treated so,,
I would also file request for records NOW either by him or congressman,,,, maybe contact them again too and ask again for some help,, sounds like pretty urgent situation,, you will be in my prayers,, best of luck and let us know,,,Jane