This sort of thing isn't without precedence. For instance, there was a commercialized Lyme Disease vaccine back in the 1990's, but anti-vaxxers kept hitting the manufacturer with nuisance suits, so they withdrew it from the market.

I wonder if the patents have expired yet. Maybe someone could make a generic version? There's a lot of money going into creating a new vaccine, since that would be more profitable, but there's nothing wrong with the old one.

https://www.cdc.gov/lyme/prev/vaccine.html

I agree that some sort of evidence for the Parkison's cure is needed. Presumably the professor has created a web page, etc, at this point.