"Sometimes they would get something, and you get your hopes up all over again, we just protect ourselves by not listening to the new sightings anymore.
"Maintaining a level of indifference to it, mostly just to protect ourselves.
"There's nowhere new to go and I can't do this anymore, it's just too hopeless. We are just trusting the police moving forward."
He said the search was "incredibly thorough" and the support they received was phenomenal.
"We have huge thanks for the friends, family and relations that came out to help with the search, just trying to find him.
"You don't know how resourceful you can be until you have to."
For the sake of Nigel's two younger siblings they celebrated a large Christmas.
"We kept Christmas going because the kids really deserved that, they have been so good through this and sometimes the most positive of us all," Chris said.
"Nigel would have wanted to be here, and that's absolutely gutting."
He said Nigel had his own Christmas traditions, a large steak and a walk in the bush with his family.
"We missed him at Christmas, he loved spending that with his family. You just think back to all the little things he did, and just having him around.
"The whole family have had lots of support and we will keep going."
Nigel has been with a fulltime caregiver since he was 20.
On the day he disappeared he got wind he was being temporarily moved from his flat because of a water cylinder issue.
Before caregivers were able to properly explain the situation, he got out of the car and walked off.
The caregiver walked after him, but found it hard to keep up so got back in her vehicle. She drove alongside him on Old Taupo Rd trying to talk him into getting back in the car.
Police have said there was nothing suspicious about the disappearance.
Since then there has been one confirmed sighting of Nigel at the Hemo Gorge roundabout about 4pm the day he went missing.
The search so far
• November 17, 3pm - Nigel Peterson was last seen at 3pm on Otonga Rd, heading towards Old Taupo Rd
• November 17, 4pm - Credible sighting of Nigel at the Hemo Gorge intersection
• November 21 - Police began the door-to-door search of more than 1200 properties in the area
• November 24 - Police used heat-seeking drones in the search
• November 25-26 - A large weekend push saw police cover the area south of Rotorua towards Tumunui
• November 27 - Heli-resources loaned their helicopter to cover a large area around SH5 and Highlands Loop Rd
• December 1 - Police spent 45 minutes giving out flyers to all cars travelling through Hemo Gorge
• December 3 - Potentially useful information was received from the area around Lake Rerewhakaaitu
• December 5 - Police temporarily suspended the ground search as they continued inquiries into credible sightings
• December 9-10 - Police and Land Search and Rescue completed searches South of Tumunui on SH5 and out towards Lake Rerewhakaaitu on SH38
• December 9-10 - Police sought the help the Behaviour Science Unit to build a better understanding of Nigel
Nigel Peterson
• 33 years old
• Slim, medium height
• Wearing a green T-shirt, light brown pants, brown sneakers and possibly a denim jacket
• Often wrings his hands and could be talking to himself
• Walks with an unusual gait and leans to the side as he moves
• It is now likely that Nigel would have grown ginger facial hair
Any information can be given to Rotorua police on (07) 348 0099 or the anonymous Crimestoppers line on (0800 555 111).