The brain is not like any other tissue in the body. The brain needs rest or at the minimum moderated stimulation. Stress cause chemical toxins to build up reducing the brains ability to recover. The brain does not grow new neurons. It can grow new axons and dendrites but these take a long time.

Those who do not have the ability to moderate stimulation may get better slowly but their improvement will be much less and slower.

Maybe this analogy will help. You have a bucket fill of contaminated water. You can clean up the bucket two ways. You can put a hose of clean water running slowing into the bucket. Slowly, the contamination will lessen. It will never get removed completely. This would be like trying to recover without removing the stress factors.

You can also stir up the water so the contamination is suspended then dump the water out and refill it. This would be like reducing the stress factors and letting the brain detoxify with this low stress environment then restarting to regain the ability to tolerate new stimulation. Low stress (quiet rest) with good nutrition will help the brain detoxify.

Even a scrape on your arm will never heal or very slowly heal if you keep picking the scab off and exposing the wound to contagions.

I hope this makes sense.

At the extreme, doctors will put a severely brain injured patient into a drug induced coma to prevent the brain from being stimulated so the brain can heal. Then, after the patient is allowed to regain consciousness, stimulation will be increased slowly. The concept of reading to or talking to a comatose patient is based on the idea that the brain will respond to "familiar, low stress" stimulations in a beneficial way.