A neuropsych evaluation will determine the type and extent of brain damage, what specific areas of his abilities are affected and why. Some determination will probably be made relative to the degree of recovery that can be expected. This information is invaluable is helping his recovery team create a care plan.
Neuropsych evaluation will tell you along with the neurological problems what all psychological problems he has due to the brain damage. They also tell you how to deal with your husband from the psychological point of view. Because one has to be psychologically fit to remain fit.