Severe brain injuries are one of the most heartbreaking wounds coming out of Iraq. It was patients at the VA Hospital with these types of injuries who most affected me when I visited.
But Raven of And Rightly So (a healthcare worker experienced with treating severe brain injuries) has some very encouraging words about the possible ultimate recovery levels of people facing these kinds of challenges. Please go read the NY Times article she references, along with her knowledgeable analysis. It'll both break your heart and give you hope.
As Raven says of these wounded warriors, "Some give all; some give all and are still with us."