I do believe that there is hope here.
I know that the body has an amazing ability to heal itself. The fact that his vital organs are functioning well is definitely a good sign. It is also a good sign that the MRI results were good. In addition, it is probably a good sign that he is moving some. I believe that you will have your brother in a stable and conscious condition soon if you don't already.
I do know that he may need extensive rehabilitation after this but there is hope and rehabilitation does usually help.
I wish you a blessed day, week, and a blessed relationship with your brother. It might help if you talk to him. I think that even if he does not appear to listen, he may be listening anyway. This may be comforting to him.
I wish you well.