I have to say I am extremely skeptical about this, but I'm not a professional historian by any means. I know you can't prove a negative, but is it at all credible?
It's impossible to prove a negative. For example, Aaron Burr had dinner with Jefferson shortly before he launched his filibustering expedition. Does that mean Jefferson engineered the whole Burr treason plot? Probably not, but no one can ever prove that beyond a shadow of a doubt.