"Doctors told her that Christopher wouldn't live beyond 20 but he defied doctors and lived to 72."
It was a different time in the 1950s, Allison says, with no state provision of housing, training or assistance for children with intellectual disabilities and their families.
She says while Christopher was never able to speak he was still able to communicate with people.
"All those who knew Chris, loved him," Allison says. "He had a wicked sense of humour, and had the most infectious chuckle. He loved his beer and enjoyed trips to the local RSA or Cossie Club in Pukekohe."
Raised on the family farm at Waitoa, Christopher's parents Beart and Lorna Ranby decided he would be part of the family and the community just as any child would.
He took part in all the family outings and holidays, Allison says, including regular trips to Mount Maunganui.
Christopher loved watching the ships at the Port of Tauranga, she says.
Later in life, Allison took Christopher on many excursions – to the South Island, up north to Paihia, to Cooks beach and Waihi beach.
She recounts a funny story of losing her brother on the beach at Mount Maunganui, only to find him two hours later at a nearby supermarket where he was helping stack shelves.
Christopher was the eldest son of Beart and Lorna, two of the early founders and driving forces of the IHC in the mid-North Island.
Lorna started the South Auckland branch of the IHCPA, the IHC's predecessor, for her son in 1950.
She advertised in the local papers calling for a meeting of parents with intellectually disabled children.
South Auckland at that time stretched north to the Bombay Hills and south to Taumarunui and, Allison says, slowly through her mum's efforts more than 33 towns formed sub-branches of the IHC, including one of the first, Bay of Plenty.
In recognition of Lorna's efforts, it was Christopher's name that was given to the first non-governmental social housing for people with intellectual disabilities in New Zealand – Christopher House, established in 1954 on Grey St in Hamilton.
Allison says her mum sat on the steps of Christopher House when it was first opened "waiting for arrest".
"The Mental Health Act of the time prevented people with intellectual disabilities from living in hostels," she says.
That facility was followed by Christopher Park, the first residential complex for people with intellectual disabilities, which opened in 1960 and closed in 1989 when such institutions were no longer regarded as appropriate.
Christopher spent time at both of those places before moving with his parents to Auckland and later Tauranga.
"Now many adult IH people live in homes in the community run by Idea Services, where they are cared for in a safe environment but where they can live and even work as any other adult would," Allison says.
Her mum devoted much of her life to ensuring those with intellectual disabilities like Christopher had the best quality of life possible, Allison says.
"Mum clearly had a gift – many spoke of her wonderful ability to speak on behalf of those who could not speak for themselves.
"She was indefatigable in drumming up support for these people at a time when any form of mental illness was totally stigmatised."
Lorna received an MBE in 1959 for this work.
She and Beart moved from the Waitoa farm in 1971 to Auckland where Lorna continued in a consulting role for the Auckland branches of the IHC.
They moved to Matua, Tauranga in 1981 but no longer played an active role in the organisation.
Christopher moved to different IHC houses in Pukekohe following his parents' deaths and lived there for about 23 years.
He then spent the last five years of his life at Selwyn Heights Hospital in Auckland – it was there that he unexpectedly but peacefully died on November 20.
Christopher is survived by his brother Paul, based in Palmerston North, and Allison, who is living in West Auckland.
His funeral was held at the Selwyn Heights Chapel, in Hillsborough, on November 24.