The TBI improvement was like improving from a 12 GCS to a 13 GCS.
It helps with motor control. Motor control is a very primitive system compared to cognition.

Neurorehab has long been able to take a TBI victim from unable to walk to walking again and even from unable to communicate to talking again with enough therapy.

Cognitive rehabilitation is entirely different.The neural networks are far more complex.

BUT, brain surgery just to administer the treatment? Never going to happen for PCS and even more severe post concussion dysfunctions.