I call shenanigans. It's "Facilitated Communication" which James Randi has pretty much proved is bullsh1t. Watch the video of this guy 'communicating', he looks at the roof and drools on himself, while some fat chick holds his hand and stabs a touch-screen with his finger, typing whatever she wants. The dude's a vegetable.
No way somebody was aware for 23 years in a coma. By the time he woke up he'd be batshit insane. Sensory deprivation for even a day can drive people insane. 23 years of not seeing anything or being able to do anything would definitely cause total insanity.