His mother Linda Smeele, who flew out to Florida immediately after learning of the injury, said last night it was a mother's worst nightmare.
"It's one of those calls that every mother dreads, at three in the morning, hearing that your son has been in such a tragic accident. I got a call from the pastor at the hospital telling me that my son is in a critical condition," she said. "I didn't sleep for 36 hours. I've been a mess.
"It's devastating. The good news is he does have some sensation of touch from the nipple-line up, and he can shrug his shoulders," she said.
"We've heard lots of inspirational stories of recoveries and we need to hold on to those. It is our dream, that it could also happen to him. His spinal cord was badly damaged, but fortunately it was not severed. So we live in hope that it could improve. Time will tell."
The accident occurred about 11am last Sunday in Orlando, Florida, at Brad's sponsor's training facility at Lake Ronix. He was attempting to perfect a trick that no other wakeboarder has landed before. He first landed the trick at the Red Bull Rising High event in Germany a couple of weeks earlier, where he was placed fourth.
"He was basically going off one ramp, getting massive air, and landing on another ramp," his mother said. "He lost control in the middle of it and slammed into the landing ramp.
"He landed on his neck. It was a full-body plant, really. He was going at speed ... it was a big impact."
The impact broke the C4 vertebrae, which had to be removed and replaced with rods and pins.
He is unable to breathe on his own, having had a tracheotomy on Tuesday to aid his breathing with a ventilator. He is generally alert but cannot speak audibly due to the tracheotomy tube, Ms Smeele said.
"He's awake and trying to talk but it's frustrating for him. We can communicate with him if we lip read well."
The wakeboarder is renowned as an innovator in the sport, developing and landing tricks before anyone else, his London-based 23-year-old brother Alex said from Orlando yesterday.
"Brad has always been the one to push the sport further and further ... as far as it would go," he said.
He was one of the first wakeboarders to land a 1080 — three full rotations in the air — and, as always, was attempting to push the limits of the sport with the latest complex trick, said Alex.
In a Facebook posting, the president of Ronix, his prime sponsor, described Brad as the leader of the team.
After pushing for years for a professional contract, suffering setbacks but never giving up, he became the glue for the organisation, he wrote.
"He's innovated more new tricks ... than anybody else on our team, or arguably anybody in our sport.
"All of those nights of tossing and turning that would leave most of us to throw in the towel on being a pro rider were finally paying off," the post said.
The family are exploring all options to ensure he receives the best possible physical and emotional recovery treatment.
It would cost about $200,000 to have Brad transferred back to New Zealand via medivac, while specialist facilities in the US are expected to cost at least $75,000 a month in care.
Alex said: "It's still only day four. It feels like it's been months."
How to help
The family of Brad Smeele are weighing up various options for his medical recovery.
If they decide on treatment in New Zealand, it will cost about $200,000 for a medi-vac flight alone.
Treatment in United States facilities costs about $75,000 a month, before surgeries and additional medical care are included.
For the next six months' care, the Smeeles are hoping to raise about $400,000 to $500,000.
Ways to donate
• A givealittle donation page has been set up in New Zealand and had yesterday raised more than $71,000.
• Some overseas donors were struggling to donate to the givealittle page, so the Smeele family have also set up a foundation and a PayPal option for donating.
• More substantial donations can be made directly to the family, who have set up accounts in New Zealand and the United States. Donors can email bradsmeelefoundation@gmail.com.
• Numerous products and services have been donated to the cause and the family intend to hold an auction.