Do you believe that rural wizards can cure diseases? Why do so many people believe it?

My father's grandmother is the so-called witch, mainly dealing with the soul of the upper body. She worships several nameless gods and has statues painted on the wall. The main step is to light incense first, and then start evocation, and constantly hang a Zhang Yuanyuan red paper on the incense, and then the paper will be hung on it, which proves that the ghost has arrived. After she talked to the ghost, her body also showed the symptoms of people who had been put on the upper body before. Ghosts usually report themselves. When a certain agreement is reached through conversation, ghosts usually leave on their own, and red paper will fall off on their own. If they don't leave, they will be suppressed by the gods they worship. After the end, the symptoms of people in the upper body basically eased immediately. Although there are psychological hints, there is no hint that the newborn child will cry all night. Last year, when menstruation's family went out of town, the child cried all night. Later, they called the old man. Half an hour later, the old man said it was from our village, and then the children stopped crying. A similar thing happened to my parents. In a word, these problems have certain scientific reasons, but science can't explain them yet.