"We miss her and every now and again you see a young lady in town and think 'Oh here's Casey' and then 'Oh, don't be silly'."
She said the loss of Kymani, who died in Waikato Hospital's newborn intensive care unit, was equally difficult because he was so young and his birth was eagerly anticipated.
"It's sad to lose a daughter but to lose a little grandson as well. It's awful. And he was such a beautiful baby."
Mrs Broughton said the family were pushing through their grief by focusing on the October 12 unveiling at the family urupa near Waingaro where the pair's double tangi was held. They want attendees to wear bright and sparkly clothing to reflect Ms Nathan's personality.
"It's going to be very emotional for us all. But we've just got to keep going. It's pretty difficult, memories keep coming up all the time but we're staying calm and patient."
She said her grandson, Hayden Tukiri, was coping as best he could.
Tukiri was jailed for his role in two aggravated robberies after the deaths but his sentence was reduced to 22 months, with leave to apply for home detention at a drug and alcohol rehabilitation facility, because of the traumatic effect the deaths had on him. A coroner's inquest into the case has been rescheduled from this month to February next year in Hamilton and is set down for nine days.
Mrs Broughton said parent support and lobby group Action to Improve Maternity (Aim) had helped the family prepare for the inquest before coroner Garry Evans.
Founder Jenn Hooper said the hearing was potentially of vital importance to public safety.
"We are hopeful as we are with every case that it will uncover areas in the system that can be done better."
She had been assisting the family with "an insane amount of work" in the lead-up to the inquest.
Mrs Broughton said if anyone wanted to support the family, they should make a donation to Aim to help with not only Ms Nathan's inquest, but others the charity takes on.
Timeline
May 21, 2012: Casey Nathan delivers her baby, Kymani Casey Nathan-Tukiri at Huntly Birthcare. She is transported after her son to Waikato Hospital and later dies.
May 23: Kymani dies in the NICU.
May 26: A double tangi is held for the pair at Waingaro Marae.
March 8, 2013: Ms Nathan's partner and Kymani's father Hayden Tukiri is jailed for his role in two aggravated robberies. The judge is lenient because of the traumatic effect of the deaths on him.
July 4: A coronial inquest into the deaths is set down for September 12 but is later rescheduled to February 17, 2014.
For more information visit aim.org.nz