Rotorua's Teimana and Soul Emery-Maaka share a brotherly bond second to none.
Although the youngest of the siblings, 3-year-old Soul is helping his big brother reach milestones the family once only hoped he would reach, while also being fiercely protective of him.
Despite a normal start in life, Teimana began to change at 6 months old, and at 9 months was diagnosed with mitochondrial disease.
Mitochondrial disease is genetic and the type Teimana has – 100 per cent Leigh disease – doesn't have a good prognosis.
His parents Levi Emery and partner Rico Maaka were told when their son was diagnosed that his life expectancy was probably between one and two years, although there was a chance he could make it to his teens.
Teimana is now 5 and beating those early odds with, his mother believes, help from Soul.
"The past two years have been really good," Emery said. "2017 was probably the best year Teimana has had. He was only in hospital twice and one of those times was because we were going away and wanted him to get better quickly.
"His seizures have dropped from sometimes 20 a day to between two and five."
She is positive things started getting better when Soul began to interact with his brother.
"Soul treats Teimana like he treats everyone else although he knows something isn't quite right. He growls any other kids who come round and touch any of Teimana's medical equipment.
"But because he is always doing stuff with him, Teimana moves more and is also a lot more vocal.
"His arrival has probably helped me a little more too as, before he came along, I wrapped Teimana in cotton wool and I'm not able to do that anymore."
She still admits she has trust issues with other people when it comes to her son.
"I do things my way and struggle to let anyone else take over."
A fulltime caregiver, Emery says she does take a little more time for herself nowadays than she ever has.
"In the early days if I went to bed absolutely exhausted after looking after Teimana then I'd feel better – I'm not quite as bad as that anymore."
Emery said she and Maaka still took things week by week with their firstborn but watching him achieve small things had been amazing.
"He can put his fingers in his mouth now. That took a while but now he's always got his fingers in his mouth. In his own unique way he can roll onto his side and, while he's on his tummy he can turn his head from side to side."
One of the hardest things about mitochondrial disease is the uncertainty.
"As part of a mito support group we've seen four of Teimana's mito friends pass away in the past four years. Kids with the disease can be doing so well and then get a cold and go downhill so quickly.
"That's always in the back of your mind."
Emery also paid thanks to Teimana's Rotorua team.
"Starship was great but when we came back to Rotorua, the medical team hadn't had too much experience with mito – it's such a rare disease.
"But now we have an awesome homecare nurse and an awesome paediatrician as part of his team."