The body is the communication between the soul and this universe, so when the brain is damaged, the communication will suffer. Not the soul.
I saw a brain surgeon on TV performing and operation while the patient was awake. He did this as he needed the person conscious so that he could ask him questions. He was operating on a portion of the brain responsible for vocabulary. He showed him pictures, and long as he could say what the pictures was, he could keep cutting out bits of his brain. However ,it got to a point where he showed him a picture, and the patient said he knew exactly what it was, he could see it was red, it had wheels, there was driver, it had a siren. But he COULD not say what the pictured vehicle was. The surgeon moved the electrode, and the patient immediately said "Fire Engine".
The patient was awake, aware able to make decisions, talk to the surgeon. Everything about the person was fine. But as soon as a tiny electrode was tested on his brain, his ability to verbalise pictures completely disappeared.
We do no understand how the brain creates consciousness, but that was a good demonstration that the brain alone, is completely responsible.
In other patients that had suffered damage, they too were completely aware and conscious, able to make decisions just like you, BUT they could not recognise the face of their wife, their children or even themselves.
So what is the soul doing in people like this?
Can it recognise pictures and people all the time, but the person whose soul it is cannot.
What then is this soul for?