An associate professor in the religious studies department at Indiana University Bloomington went to Mozambique, to a Pentecostal faith healing group specializing in healing the blind and deaf. They tested the hearing and vision of some people, watched as the faith healer put his hands on them and made their ears hear and their eyes see. Then they published this in a journal as finding that proximity of the prayer is key to having it work.
I think it shows some people are susceptible to being gulled by faith healers. The people they tested were shills, and the people doing the "healing" were frauds who put one over on the "researchers."