Carson seems to believe fatigue can be treated by modifying expectations.
When I read that, I feel misunderstood because the experience of the illness includes the strong experience of POWERLESSNESS of positive expectations, attitudes, thinking, and the difficulty predicting things precisely, and the POWERLESSNESS to overcome fatigue despite extreme effort and motivation. More effort will just lead to worse fatigue (over time). That's why I have learned to not struggle too much... not because I'm lacking the ability to be positive and motivated, but because I know it will not work. The positivity is POWERLESS and leads to futile struggles that end in crashes that make things worse.
It's bordering on insane to suggest that fatigue can be treated by modifying expectations. He is probably confusing "getting patients to talk about fatigue differently in a medical setting or filling out questionnaires differently" with "successfully treating fatigue".
He is an academic in an ivory tower that is clueless about the real world.