However, he had heard Darnell was doing well from his own son and daughter, who were with the little boy in hospital.
Mr Carroll said he was given the option to surrender the dog, 3-year-old pitbull Caesar, and did so without a second thought.
"After [the attack] I didn't think I would be able to go on with that dog."
Caesar is being held at the Manukau animal shelter while Auckland Council investigates the attack.
"There will be a meeting to determine the next steps tomorrow," a council spokesman said.
After surrendering the dog to the pound Mr Carroll said he expected it would be euthanased, although he would not be told when.
He wanted the dog to be put down, he said.
Darnell was rushed to Middlemore Hospital and came out of surgery around 2am yesterday morning.
It's still unknown what sparked Caesar's attack.
The pitbull was usually locked away when children were around, said Darnell's mother, Virginia Minarapa.
The attack occurred in the garage after Darnell jumped on the bed to play Playstation, giving Caesar a fright.
He had just been dropped off by his mother, who was reversing out of the driveway when the dog started mauling Darnell.
"I was in the driveway [when it happened]. Everybody was crying, screaming, panicking and upset. Only one person saw it happen," Ms Minarapa said.
Blood stains are visible on the floor in the garage where the attack took place.
The Herald understands the attack occurred on a Housing New Zealand (HNZ) property.
HNZ spokesman Glenn Conway said the agency was working with police to establish what happened in yesterday's attack.
"We cannot comment further until we have all the facts," he said.
Meanwhile, the incident has prompted the New Zealand Association of Plastic Surgeons to call for education, licensing enforcement and even ban breeding of dogs deemed dangerous.
"Plastic surgeons are seeing these injuries around twice a week, the latest a major one in south Auckland," said association president Dr Sally Langley in a statement.
"These children suffer pain and severe physical and psychological trauma. It is a very difficult time for their families. Many need multiple operations and suffer permanent and severe scarring."
According to two studies presented by New Zealand medical professionals last year, hospital admissions for people with dog-bite injuries average two a day.
Data also shows that over the last 10 years, more than a third of these were children, mostly with facial injuries and the number of cases per year continues to rise.
More than half are to the face and this correlates with the age of the patient - children more commonly have facial injuries because they are closer to the ground.
Plastic surgeons have called for education for parents, care-givers and dog-owners about the care of children around dogs, a review of the licensing of dogs and enforcement licensing and of penalties, and an investigation into the banning of certain dangerous dog breeds.
A study published in August found 99,000 dog bites had been recorded nationally in the decade to 2014 - with more than 5800 requiring hospital treatment.
Incident rates increased from 10.5 attacks per 100,000 people to 14.3 over the 10-year period.
More than 2500 charges were made under the Dog Control Act in the past five financial years. Just over 350 dog destruction orders were granted in that time.
Recent dog attacks:
Dec 1 2015 - A woman is attacked by three Irish wolfhounds while delivering mail in Dunedin. The attack was so vicious the woman recalled thinking she was going to die.
March 4 - A woman is attacked by two dogs on a South Auckland property. She was taken to hospital in a moderate condition.
March 10 - Blockhouse Bay Intermediate School went into lockdown after a teacher was attacked by two vicious dogs on school grounds.
March 28 - A 10-year-old Waiuku boy has his face badly bitten by his best friend's family dog. The dog was immediately put down.
April 5 - The grandfather of a 6-year-old boy mauled by a dog pleads guilty to a charge of being the owner of a dog which caused injury. His dog attacked the Tauranga man's grandson in October last year while his grandson was trying to feed the dog.
April 6 - Christchurch police shoot and kill a dog during a property search after it starts attacking a police dog.
April 8 - Darnell Minarapa-Brown, 8, is attacked by his uncle's dog, receiving nine facial puncture wounds which require surgery. He may never regain feeling in his top lip due to the injury caused.
