A haematoma, broken nose and eyes so swollen he couldn't open them were just a few of the injuries he had sustained, she said.
"They're not 100 per cent sure but he might have ongoing problems because of his brain. His nose is pretty crooked, he can't eat, he's got stitches all through his mouth and a huge open wound under his lip.
"He also needs to see a dentist for his teeth because they're painful and chipped. So it's going to be an ongoing thing."
Last night a Hawke's Bay District Health Board spokesperson said Ayden was in a stable condition in the general ward.
Ms Kairau said she believed Ayden had taken off to a party on Chatham Rd that night and, after leaving, suffered an unprovoked attack in Ron Giorgi Park.
"He filled me in on what happened but I don't know what happened after the beating. He was unconscious but somehow he got back to the house [where the party was] and they rung the ambulance."
The mother said the family lived in Frimley and, while they had family in Flaxmere, her son knew better than to roam the streets at that hour.
"My son is a really good boy. He just doesn't listen and he was just bored and wanted to go to a party because I never let him go to parties."
She believed the person who assaulted her son was unknown to him and said this, combined with the boot marks that covered his body, haunted her.
"I wasn't there but when I'm quiet and settled I'm constantly getting flashbacks and images in my head of my boy lying in the dark on the ground in the cold with this happening to him, people he doesn't know and him not knowing why, with no one around to help him. I just can't handle it."
A police spokesperson said police had received a report of an assault in Flaxmere in the early hours of Sunday morning, but could not comment further.