Initially his prognosis was positive, with doctors giving him a 90 per cent chance of beating the disease but eight months down the track his survival rate has dropped to 10 per cent.
Brunton's body rejected chemotherapy and stem cell treatment was no longer an option.
"The only chance we have left is an immuno-therapy trial in the US but we are in a race against time," Brunton-Rennie said.
The ground-breaking CAR-T treatment is yet to surface in New Zealand but clinical trials are being held in Boston in the United States.
The way the treatment works is the immune cells - known as the T cells - are taken out and are genetically engineered into "killer cells" which takes around three weeks before they are inserted back into the blood.
All together, Brunton-Rennie said he would spend around six weeks in hospital.
Through a "absolute miracle" Brunton has been booked in for a consultation next week but payment is needed upfront.
For international patients the treatment costed NZ$1.2m with other medical bills expected, plus flights and accommodation.
"We are willing to sell our house, cars and everything we own to get Kurt that treatment. We have no choice, he will get there," Brunton-Rennie said.
A Givealittle page was created on Saturday in support of the family and already more than $86,000 has been raised.
Brunton-Rennie described her husband as the "kindest and most beautiful man" you would ever meet.
Father's Day had been extra difficult this year.
"He just opened his father's day gifts and we were all just crying because part of us is scared and the other part of us is just extremely hopeful."
On Wednesday their baby daughter Sage will turn one.
"She's daddy's girl, and deserves to grow up with her Dad," friend Emma Mildon wrote on the Givealittle page.
Next week Brunton will fly to Boston with his mother while his wife stays home to look after Sage.
"Given we get the green light from the consultation, I will join him for two weeks of the treatment while my mum looks after Sage here," Brunton-Rennie said.
Brunton-Rennie said she wanted to tell her story because in the short time-frame since her husband had been diagnosed she had meet so many other families going through the same thing.
"There was a woman in hospital just last week holding what looked to be a six week old baby and her husband was sitting in the chair crying and she was trying to keep it together.
"It was obviously his first treatment and they had just found out and I wanted to give her a hug and say I know exactly how you feel."
She said being able to share their story and bring some light to the necessity of bringing an immuno-therapy to New Zealand was so important.
