"When I went to medical school, like 20 years ago, there were very various kind of one-liners you get in medical school about, you know, ways of understanding a problem. And the one liner you'd get about brain injury was, 'Damage done,'" Dr. Schiff says. "What's done is done. Structural brain injury is unchanging."
"So with patients in minimally conscious state, it's not true to say, 'What's done is done?'" Cooper asks.
"I think we know enough now to know that there are some minimally conscious state patients where that statement is false," Schiff says.
Dr. Schiff believes Don's awakening may have been triggered by a Parkinson's drug his doctor gave him.
What's even more remarkable is that another drug has recently been shown to have similar effects on some minimally conscious people. The case of George Melendez is perhaps the most dramatic of all. George suffered a brain injury when he crashed his car into a pond and nearly drowned. Weeks after the accident doctors told his mother, Pat Flores, her son would never get better.
"What you see lying there in the bed is as good as it gets," Pat remembers of the diagnosis for her son. "That's as good as it gets. He's never gonna be able to do anything. He is a vegetable."
George was in a minimally conscious state, but for years Pat was determined to reach him. She cared for him at home, while searching for new treatments.
Pat believes George was always there, just unable to communicate.
One night in 2002, unable to sleep because of his moaning, Pat gave George Ambien, a common sleeping pill used by millions of people.
"I noticed the room got quiet and in my mind, I'm thinking, 'Wow, that pill's really good. It really knocked him out.' And when I looked over, instead of seeing a sleeping George, I saw a very much awake George with his eyes wide open and just scanning the room and looking," Pat remembers.
For the first time in five years, Pat heard her son speak.
The next day, sensing she was on the verge of a breakthrough, Pat gave George another dose of Ambien through his feeding tube. George's step-father taped the transformation.
Within six minutes, George went from being unresponsive -- moaning and shaking -- to quiet, alert and answering questions.
Asked what kind of questions she asked her son, Pat says, "If he knew where he was at. If he knew what had happened to him. If he was in pain."
George told her he wasn't in pain. "He said no clearly, which that was a big relief," she recalls.
Pat doesn't know why the Ambien works, but she's been giving it to George every day now for the last five years.
60 Minutes helped arrange for George to see Dr. Schiff of Cornell. He performed exams to see if George's reaction to Ambien is real or just his mother's wishful thinking.
First, Dr. Schiff did a PET scan of George's brain off Ambien. The frontal lobe, the area responsible for behavior and language, was yellow, indicating greatly reduced brain activity.
The next day, after he was given Ambien, George was put back in the scanner. The frontal lobe, seen earlier in yellow, was now bright red.
"So we've just learned something here. Today's scan looks like it's about two or three times as intense, metabolically," Dr. Schiff observed. "That's like a big deal. His brain is turned on, with this stuff."
Asked if he has seen Ambien work on other patients, Dr. Schiff tells Cooper. "I have. And about a year and a half ago, I would've said, no. … And now, I've seen at least three cases."
"And do you think there are more people out there who could benefit?" Cooper asks.
"I think you're gonna find a subset of patients who respond to it," Schiff says.