But two days later he was still struggling with his breathing and was taken to Hutt Hospital.
Brock was sedated so that a breathing tube could be inserted through his throat and into his lungs to do the work for him.
Once he was ventilated he was taken to Wellington ICU and when he was still on it 24 hours later he was flown to Starship Children's Hospital in Auckland on Saturday.
He has not woken since while his body recovers from pneumonia and bronchiolitis.
His mum Abbie Wilton said it was heartbreaking watching her usually active son lying lifeless on a hospital bed.
"We haven't seen his cheeky little face awake since Thursday."
Doctors did not know how long he would be asleep for at this stage.
"He just needs to get better and he's not," she said.
"He needs to stay sedated until he's breathing better, because obviously once he's awake he needs more energy to breathe so he needs to breathe very well by himself while he's asleep," Wilton said.
"It just a waiting game to wait for it all to pass really."
They couldn't wait for their cheeky little boy to wake up and start chasing his 5-year-old sister Harper around the house again, Wilton said.
"He's just a cool little dude. He spends most of his time chilling out, listening to music and dancing around and climbing up on the TV cabinet."
Harper also wanted to play peek-a-boo with him again to make him laugh.
Brock has had bronchiolitis a couple of times in the past, but this was the first time he had been ventilated. He was born 11 weeks early and has weaker lungs making it harder for him to breathe.
Weaver and daughter Harper flew up at the weekend to be with Brock. His family is staying at Ronald McDonald House.
Wilton works as a self-employed home-based child carer and Weaver has only recently started a new job so did not have much annual leave to draw on.
"Brock is the most gorgeous wee boy with the coolest little attitude. Brock's parents are just as amazing too, they get behind and support everything they can even with busy lives," Russell posted on the Givealittle page.