What are the chances on recovering from brain damage?

A friend of mine recently got into a car accident where the car hit a center divider and flipped over. He was on his way to work midday. Right now he's conscious but there was severe brain damage to the point where he can't function. For example, "there's no one home".... He's constantly moving around, eyes are open but can't function like a normal person would. The doctors said that he's going to need a metal plate to cover the lossed part of his skull... So back to my question, is there any way he will be able to make some sort of recovery to the point where he can at least speak again and walk and eat and have a thought? What are the chances?