However, there is now quite a bit of talk among the sceptical community that the helper - who is 'helping' him move his hand on the keyboard - is actually doing the typing herself, with no input from him. I don't think people are saying that she is lying, just that she has fooled herself into thinking she is communicating with him.
Here's James Randi explaining his scepticism. I don't actually like Randi or his manner, but I think he may be right. Here is PZ Myers on the same topic. And here is the American Psychological Society statement on facilitated communication.
Here is a video, which seems to show the helper is overtly doing the typing (from 12 seconds in). I do agree with Randi that there needs to be some control or test that these are really his own answers. I'm surprised it has been reported so uncritically.
Here is a touching comment from a nurse on metafilter.
Families will run with this story as only a deeply loving person can: they refuse the possibility of death to their beloved. They will tell us, "But, didn't you hear on the news? They said that man was dead... who are you to decide?" Unfortunately, the rational answer "We are medical professionals" does not hold weight against arguments of the heart. We can bring so many back from the brink of death, but once the brain has been compromised, the body can live on. Family members will spend years convinced that their loved one is somewhere inside that husk of humanity; if only they could just convince others to believe them!
Then some person, perhaps without evil intentions, will tell them a way of proving it: facilitated communication. Just let this trained person hold this man's wasted hand and guide it to the right keys. And the aide will spell out those words that they have longed to hear: I love you, I miss you, I have been so lonely....and in their joy the family will reject reality just so they may have one more chance to communicate with the husband, wife, child or parent they lost so long ago.
Of course this does not prove he isn't conscious. He might be conscious and helpless, while someone moves his hand in a typing movement. But my hope is that he hasn't been hellishly trapped in a paralysed body, fully conscious, for 23 years. I hope he has been and still is unaware of any suffering.