They cant be proven to be legit, its impossible atthis point.
1. Family deny's they are from them, and they are his personal files.
2. Even if the ability to create documents like this were possible back then, the specter has been raised that too many variables exist to prove authenticity.
3. They need an unimpeachable individual from the unit he was there or even typed them in the colonels stead, either way that will create more questions.
4. The DOD themselves may have to be the arbitrator on this.
yet in the SIX WEEKS OF INVESTIGATING cbs NEVER did 1-4