If he had a "locked" private drawer where he kept the cya files, then who would have had them. When he left the guard he would have boxed them up and taken them home or destroyed them as he wouldn't need them any more. If he had taken them home, certainly, his wife/son would have access to them. Who else would have any reason to keep copies for so long and why would copies to given to anyone from his private files. I remember going thru my father's paper after his death. It's been over twenty years and believe me, I don't have any of his papers laying around.
This just doesn't make sense that someone would keep documents even if you thought they had existed. And where are the others? Surely, there would have been more than 4-6 pages.
Having a "locked" private drawer to stash CYA memos is laughable. Locked drawers would be the first thing an IG inspection team would want to examine.