"This didn't have to be," he said.
"The burns are everywhere," he said. "It's the legs, it's the arms, it's his back, it's his buttocks… it wraps around to the front."
The cadaver skin, Namias said, was stapled to what's left of Brewer's natural skin to give the excised wounds a chance to heal and regenerate tissue. A common practice in the burn unit, the body -- very immune-suppressed because of severe injury -- typically accepts the new skin without rejection for some time.
Eventually, Namias said, Brewer's body will begin to reject the donor skin. When that happens, his doctors will assess how much grafting he'll need to cover what didn't regenerate.
In addition to worries of rejection, doctors are also battling infection. Patients burned as severely as Brewer also may experience heart arrythmia, low blood pressure, ventilator complications and blood clots.
"It's just a veritable minefield of problems we're constantly navigating in the ICU," Namias said. "That's why I never say they're out of the woods, until they're really out of the woods. Until, even, they've left the hospital."
And Brewer, he said, is not yet out of the woods.
"The patients with burns, if they're not going to survive, they don't typically die right away," he said. "It's usually later on from complications from the ICU."
Namias said Brewer has been able to squeeze his hand when asked and thinks he probably recognizes that his mother has rarely left his side.
"At this point he probably could understand when it's a voice that he knows," he said. "But he won't remember any of this. He's in a fog right now."
Namias said the teens' mother, Valerie Brewer, has been "a trooper," leaving only when her son's dressings are being changed and giving her doctors her full trust.
Brewer told "Good Morning America" shortly after the attack that the violence against her son was "unimaginable."
"People really need to wake up and see what's going on with this generation. They need to take hold of our children and really do something," she said. "The violence across our nation, across our world with our children is getting stronger and stronger, and we need to stop it now, so this doesn't happen to somebody else."
Namias said that if Brewer survives his injuries he does have a chance for a productive life.
"We have people who have survived 80 plus percent burns," he said, pointing to former patients who have gone on to get married, have children and earn a law degree. "If he gets through this, he can have, I think, a good quality of life."