The article says that "every possibility has been explored" before undergoing this treatment, and that "his team has sent patients back to the referring special

The article says that "every possibility has been explored" before undergoing this treatment, and that "his team has sent patients back to the referring specialist, recommending more tests", so it clearly isn't some kind of "mental health catch all". Also bear in mind that stress is a known trigger for MS, and psychological therapy has shown to be effective at reducing MS fatigue (see for example, Rona Moss Morris' recent trial, and others), so we're perhaps close to coming full circle with MS, recognising that psychological factors are important in triggering it, and also in treatment. (Although I suspect when I say "close", we're talking about another 50 years before neurologists -- especially in the USA -- get the memo).