Who is Steven Brandt from Word of Honor and what is their importance?

Steven Brandt served as one of the sources for the book written by Andrew Picard. He was a conscientious observer, who served as a medic under Tyson. Tyson recounted an incident in which Brandt apparently consumed some sort of nitrates in an effort to be sick enough to avoid combat. Tyson berated him for the action. By the time Picard interviews Brandt, he's an orthopedist in Boston. When he takes the stand, he provides a distorted version of events, including the fact that Tyson ordered the massacre of the civilians in the hospital. Brandt was the medic who treated Tyson when he was injured, as well as the man who overdosed Tyson on morphine, and almost killed him. When Kelly testifies that Brandt hates Tyson because he caught him raping a young girl, Brandt quickly leaves the court and isn't heard from again.