In the Te Rapa district of Hamilton, Fonterra tanker drivers know that every evening their biggest fan will be waiting for them on a dairy farm on Reid Road.

Fonterra's milk tankers are Andrew Oliver's favourite thing in the world and local tanker drivers have long known that Andrew won't go to bed until they've been on the farm.

But when it became unmanageable for his 65-year-old parents, the world's biggest dairy exporter stepped in to help.

They changed their milk tanker schedule in the entire district so that Andrew would go to bed on time.

Andrew Oliver is one of about eight people in the world living with Fryns-Aftimos syndrome - he's the oldest known to have it and the only one in New Zealand with the condition.

The extremely rare syndrome is the result of a mutation in one of his chromosomes which means that, at 35 years old, he has the mental age of a 6-year-old and suffers many other symptoms.

For the past 15 years he's had a special relationship with Fonterra tanker drivers.

Ken Oliver, his father, said Andy discovered the tanker when the farm went onto the night shift for milk pick up.

"[He] learned what it was, came out to see it occasionally and once in awhile would talk to a driver. But then with Andy, the normal thing is with something like this - it would become a habit. And so he had to be out to see the tanker. That became part of his nightly routine."

Andy's nightly routine consists of a list of things he has to tick off.

Every night he draws a picture to give to the tanker driver, he has to watch the weather report on the 6pm news, then he has dinner and a bath.

But the last thing to tick off - is the tanker.

Ken said that if the tanker hadn't come, Andy wouldn't go to bed. For him, waking up at 5am to tend the farm, it became a struggle.

"We simply didn't know when the tanker was coming. You might get 2am in the morning or something like that and he wouldn't go to bed until the tanker had come."

For over a decade, Andrew's parents managed his tanker visits until one day Ken says he came to a breaking point.

"Deirdre had just been diagnosed with having had a minor stroke, I was absolutely out on my feet trying to keep the farm going. Surviving on three or four hours sleep and I'd just run out. I'd hit the wall and so I phoned the call centre and actually started crying on the phone, I was just so shot.

"I just said look, my life has just become impossible and just explained what was going on. I need sleep and I can't get sleep until this boy's in bed."

The person at the call centre decided to help.

Photo: RNZ

Fonterra is the world's largest dairy exporter with about 10,000 farming families as stakeholders.

After hearing about Ken's call, the company decided to change their entire milk tanker schedule in the Te Rapa district to make sure Andy could get to bed on time.

Ken is now guaranteed a pick up anywhere between 6:30pm and 8pm.

Tanker driver Kevin said Andy draws them a picture each night and they put them up on the wall at work.

"It's not something we encounter everyday, we can tell you that... It's a special relationship."

On top of Andy's rare syndrome, he also has five types of epilepsy.

So the Te Rapa district tanker drivers have been briefed on health and safety procedures and what to do if Andy had a seizure during a tanker visit.

"A lot of us guys that have been here before, we know what to expect and we have an in cab screen which has a warning along the bottom to make sure drivers are reminded to be careful going down the track just in case Andy's floating about," Kevin said.

"That's programmed into the screen and would come up every time that vehicle comes into this farm, it would come up before we go."

These drivers mean a lot to Andy, but Kevin says Andy means a lot to them too.

"We had one of our drivers come out and he noticed that Andy's bike was looking a little bit dilapidated and he came back and sort of ran past the idea at a team brief meeting and we all thought that was a very good idea."

So the district's tanker drivers held a sausage sizzle fundraiser to buy Andy a new bike and company staff from all around the world pitched in to help.

Ken said riding his bike is one of the few things Andy can do independently, which makes visiting the tanker a huge part of his life.

The tanker drivers have supplied Andy with a uniform - a high-vis Fonterra shirt and a hat and have also given him a model tanker which is a part of his treasured truck collection.

Ken, who has his PhD in chemistry and has been a dairy farmer for 40 years, said the change in pick up time has meant a lot to the family.

"A big outfit like Fonterra doesn't have to do that. They simply could've ignored the request but no, they came through. And we're very grateful."

Kevin said the 15-minute visit to the farm to drain its milk vats every evening is a special treat for the tanker drivers on that shift.

"We like to come out here. You realise that you're lucky, how lucky you are that we're able to do this. If we can make Andy's day well, hey that's the icing on the cake."