Why not sue faith-healers for malpractice?

I know a person who has a partially displaced hip, old compression fractures of the lower spine, walks around in pain every day. Doctor says “use your cane, it will keep the discs from deteriorating further, take pressure off the back and the hip, you’ll have a lot less pain”.
But, somebody told the person, many somebodies over the course of decades, that to use a cane would be “admitting disability, ‘name it to claim it’ and it would block God from healing you”.
This is the same Prosperity Gospel bullshit that if you believe enough God will bless you with lots of money, property, shiny new cars… “name it to claim it” or as some more cynical preachers put it “blab it to grab it”.
What’s that? It’s not working? Well then, just send us 49.95 for the latest copy of our book on how to claim the blessing through faith.
Of course, if it still doesn’t work, according to the scam, it’s your own fault for not having enough faith.