"He's already in heaven," Oliver's aunt Nina told the Atlanta Journal Constitution not long after her nephew died.
Oliver, a football player at Douglas County High School, west of Atlanta, reportedly drank four gallons of fluids -- two of water, two of Gatorade -- during football practice on Tuesday last week. Oliver's mother, who picked her son up from football practice, says he was complaining of cramps and collapsed shortly after arriving home.
His family rushed him to a hospital in Marietta, where he was put on life support but never recovered. Doctors say Oliver suffered severe swelling around the brain as a result of over-hydration. An official autopsy is forthcoming.
"It's incomprehensible," Nina Oliver said. "We had a healthy, beautiful, vibrant young man."
"The crisis team will be at Douglas County High School to help students and staff cope with this loss," the high school's principal, Dr. Tim Scott, told local NBC affiliate 11Alive. "We suggest parents discuss this matter with your children and respond to any questions that arise."