Her daughter had made a directive stating that she did not want tube feeding used to prolong her life, Mrs Collins said. Nor would she permit the use of thickened fluids, which were used to maintain fluid intake in a person who, like Ms Dark, had an impaired ability to swallow and was at risk of inhaling or choking on the fluid.
Huntington's disease is caused by a faulty gene that can lead to personality and mental changes, jerky movements and trouble walking, speaking and swallowing. People usually survive for 15 to 20 years after the first signs of the disease emerge.
It is an inherited disease which took Ms Dark's father and her grandmother.
Along with an unsentimental pragmatism, she has a sense of humour about her plight.
"Hello, my name is Kimberley Dark and I'm an alcoholic," she told a conference in 2008. "Oops, wrong meeting."
Her mother talked to her about Huntington's disease from when she was 11 or 12. She knew that Dave, Mrs Collins' second husband, was not her biological father.
"She knew she had a biological father," Mrs Collins said, "and we just talked about how he had this disease in the family and she had a chance of having it when she grew up."
As well as being open about Huntington's disease, Mrs Collins, a funeral director for eight years and now a crematorium manager, has a pragmatic approach to death.
"Death, for me, is part of life."
Aged 20, Ms Dark was tested for the Huntington's gene mutation. It was positive.
This spurred her to get on and live her life - and to make the difficult decision not to have children.
She had already had success in sport as a teenager, making it into rep teams for softball and netball.
"Because she knew she didn't have a long life ahead of her, she put things into place. She did her OE when she was about 22 and then came back and met her [future] husband, Justin."
"She was already symptomatic so ... we had talked about the disease and how it would progress but that didn't put him off marrying her. They married seven and a half years ago and she lived with him until March, when it just became too hard for him to have her at home ...
"He visits her sometimes four times a week. They've got two little dogs, he takes the dogs to visit her or he'll take her home for a while, or they go out, he takes her to the rugby, she's an avid Canterbury supporter, and she has a lot of interaction with us as well."
Ms Dark worked as a caregiver at a facility for people with intellectual disabilities until three years ago when her symptoms made her too unsteady.
Mrs Collins split from her first husband when her daughter was aged 2. He hadn't been diagnosed at the time, but in hindsight Mrs Collins sees that the break-up of their marriage was related to Huntington's.
"He had the psychosis side of it quite badly, where Kimberley doesn't have that ... the movements are worse for her. [Her personality changes are only] very slight. She's still got a very quick wit and a wicked sense of humour.
"She's got the severe movements [disorder], she's unsteady on her feet and she can no longer dress herself or shower herself. She's fed [by someone else] 85 per cent of the time.
"She has an iPad with a program on it to tell people what she wants or how she is feeling. She has a couple of games on there that she loves and plays and she will play music. She has very limited speech now... but she can still sing, because singing comes from a different part of the brain."
Despite her plight, Ms Dark has never expressed any regrets to her mother about the disabilities and short life dealt out by her genetic inheritance.
"She decided to get tested so she could work out what she was going to do with her life because one of the major impacts on her life is that she chose not to have children so she couldn't pass the gene on."
In statements reported by the manager of the Christchurch care home where she now lives, Ms Dark said she thought about how life might have been without the gene mutation, "but it doesn't worry me. I have lived life to the full to fit everything in."
She wanted to have children, so the decision not to do so was a hard one to make. However, she was confident she had made the right choice: "[I] didn't want to pass the gene on."
Mrs Collins said she believed that was the right choice.
"I would love to see Huntington's disease wiped out. The only way you're ever going to get rid of it is outbreed it. So what Kimberley has done, and a lot of other young ones who have done the same thing, is being very responsible for making sure the disease does not carry on through her family."
Huntington's disease
* Inherited fatal brain disorder
* Affects about one in every 10,000 people
* Caused by mutation in a single gene
* Gene makes abnormal protein that kills brain cells
* Each child of a parent with the disease has a 50/50 chance of inheriting the faulty gene
* Symptoms usually appear in the 30s or 40s
* Sufferers usually live a further 15-20 years
* Causes jerky movements, loss of co-ordination and personality changes
* No treatment.
