I think the article/interview mentioned that the benign tumor was removed from an area adjacent to the region that regulates anxiety, so I took that to mean that there was collateral damage from the surgery.
At least some self-repair/healing should occur with time. But, he'll likely need to manage the symptoms the rest of his life. At least they know what they are dealing with. 50 years ago, this would have been a mystery and there would have been few if any resources for comfort or care. Modern medicine is pretty miraculous.
