After a thorough glance, it seems a little iffy, although still some cause for alarm. Prions are definitely a problem, and the vast majority comes from factory farming. It really isn't safe to eat the brains of your own species on a regular basis, and eating infected meat is bad. Whether this will become a time bomb, I don't know.
He talks about alzheimer's sometimes being prions. Looking at the symptom list, there seems to be quite a few obvious symptoms with cjd that would be noticed as incongruent with alzheimer's (seizures and early coordination impairment.) Given alzheimer's possible cause of aluminum crossing the blood-brain barrier with help from fluoride and our increasing exposure to both, its no wonder industrial (water fluoridating) countries have tripled their alzheimer's rates. I would be curious to see if there was some known variant of alzheimer's that includes these symptoms, and compare. Doctors have a lot of problems, but that cat would be too hard to keep in the bag if the numbers were true.
http://www.fluoride-journal.com/98-31-2/31291-95.htm <- fluoride and aluminum study.
CJD also has a variant with a very fast incubation. Wikipedia says its rare. Maybe that can't transmit through infected meat, or non-humans can't get it. If there was a sudden outbreak of vCJD, I would be concerned about the implications of the classic variety laying in wait for people with much higher numbers.
Basically I think he might be right, but with some hyperbole thrown in. Its another strong reason we shouldn't eat factory farmed meat and why civ needs to go.
As for the poor cows and sheep ... jesus.