The logic is: we have no idea but must do something, surgical implants are something, let's do brain surgery and implant something!
My father died at the age of 82 from late stage Parkinson's, never got dementia but eventually whatever neurons in the brain control movements, they fail to do so not just for movement but also vegetative processes such as swallowing and gut transit so ... one cannot live without that. Also those neurons die so that can't be good. No amount of waves and vibrations can compensate for dead brain tissue.
Hard pass on the calomel. Come back when you actually got something that works.
Bloodletting has some conditions it's actually appropriate for too.
Not sure mercury poisoning is going to turn out to be safe and effective anytime soon, though.
I'm not advocating for this, but if people are going to do it with informed consent, might as well collect proper data to try to determine if it objectively works. Snake oil that works, if it actually works, is something that works.