As somebody with chronic pain I think Sarno is a total crank. It has been decades and TMS still hasn't been demonstrated in a way that's objectively measurable. He puts forward what should be testable hypotheses about what's going on in the body and yet still can't publish anything showing it's actually happening. When you read the forums for his books it's a bunch of people cultishly telling each other that they need to believe in order for it to work.