Anything's possible. But without much better evidence than these guys seem to be offering, I wouldn't touch them with a barge pole.
Your "even better" suggestion seems pretty ridiculous to me, by the way. "Want to know whether this thing that seems like a ghoulish fraud preying on people desperate for a cure is real or not? All you have to do is find someone with the disease they claim to be able to cure, persuade them to go and do this costly, risky, probably fraudulent thing, and see what they say about their quality of life is afterwards!" And even if they do manage to persuade someone to do that -- all they get is an n=1 single sample, which is pretty hopeless evidence for anything, especially for a disease like multiple sclerosis which commonly comes and goes in mysterious ways.
The fact that they've been running for 30 years proves nothing. See e.g. https://www.mcgill.ca/oss/article/quackery/hoxsey-hoax for another example.
Anything's possible. But without much better evidence than these guys seem to be offering, I wouldn't touch them with a barge pole.
Your "even better" suggestion seems pretty ridiculous to me, by the way. "Want to know whether this thing that seems like a ghoulish fraud preying on people desperate for a cure is real or not? All you have to do is find someone with the disease they claim to be able to cure, persuade them to go and do this costly, risky, probably fraudulent thing, and see what they say about their quality of life is afterwards!" And even if they do manage to persuade someone to do that -- all they get is an n=1 single sample, which is pretty hopeless evidence for anything, especially for a disease like multiple sclerosis which commonly comes and goes in mysterious ways.