"They've still got some work to do. He's got serious burns to his back, neck and right ear. It was quite dangerously close to his airways."
A 17-year-old youth had been arrested and charged with wounding with intent to cause grievous bodily harm. He would appear in the Hastings District Court on August 23.
Mr Moorhouse said he could not rule out further charges or arrests.
A friend of Hayden, Jade Penney, heard about the incident from a friend on Facebook on Sunday.
"I was just horrified. I don't know who could have done that."
She had seen fist fights and altercations at parties, but nothing like the viciousness of this attack, she said.
Hayden had had broken arms and other injuries in the past, and had a lot of support so would manage, she said.
"He's got a lot of people beside him. He will cope."
- APN