The faith healer could be under the delusion that their particular brand of insanity is not in conflict with reality... still, it would take a fantastically high degree of incompetence to have been active long enough to build up a reputation that would make somebody trust their life to you, but still think that it works.
So it's a fairly good bet to place practically all the blame on the faith "healer". Actually... no.
It would be ignorant to place blame only on the faith healer. He didn't do it on his own. Everyone who knew what was going on, and were in a position to stop it, should share some of the blame as well. Friends and family of the deceased, the faith healer's partners, and - most importantly - society for allowing "healers" to continue operating. All of those are guilty as well.
Well, maybe that's a distraction. Is society responsible for all crime as well? Crime can, after all, be prevented with the right knowledge and correct applications of it. I don't think that's quite the same though. Not only would proper crime-prevention require active social engineering on a huge scale, but society currently actually tries to combat crime as best it can - it just isn't extremely good at it. The same is not true when it comes to things like faith healing, considering all the utterly insane things the SGU panel frequently comments on. I don't even get the impression that it is widely condemned?