Unfamiliar with natural remedies?

A fmaily member is going to a person who claims to be a doctor, but isn’t. She calls her check ups "well visits"… and when she is there she plugs the patients hand into a glove type thing and it spits out what is wrong with them… such as "you ate bad shellfish 7 years ago and the toxins are still in your body.". Can someone explain to me how this works, or even scientifically how it is possible?

I’m also looking to find natural remedies for common ailments or sicknesses.