The realm of what is 'possible' is extremely large. This is exactly a reason why serious people without an agenda tend not to play this conjecture game and stick to evidence-based facts.
What has he to prove and to whom?
I'm as distrusting of establishment forces as anyone (and heck, maybe that's part of what predisposes me to take this more seriously), but everything about this seems genuine to me. And while I don't think he's entirely above reproach, I think he's a really good guy and someone who is unlikely to mislead or engage in the kind of undue speculation you're talking about.