I recently learned that the coma man spoke through a facilitator. This is from the article:
Such a test was already done in the 1990s when something called "Facilitated Communication" (FC) was all the rage with autistic children who, just like the Coma Man, "suddenly awoke" from their long sleep and began talking up a storm and sounding all the world like perfectly normal bright children, some even returning to school to take classes. Only they weren't. Normal. Or talking. A facilitator stood next to a child, held his or her hand firmly in a grip with the index finger pointing down over a keyboard, then typed. In controlled tests by experimental psychologists, a photograph of an object was shown to the facilitator and a photograph of an object was shown to the child. Neither one saw what the other one saw. Sometimes the pictures were of the same objects, sometimes they were different. Result: whatever the facilitator saw is what got typed, 100% of the time, and never (0%) did what the child see get typed unless it was also what the facilitator saw.