The Johnsons have put it down to the alternative therapies they use to treat Elyse, instead of chemotherapy and radiation that doctors recommended.
Every day Elyse has cannabis oil, TBL-12 or sea cucumber, Vitamin C, turmeric and oils.
But the therapies are hugely expensive. The family has raised $90,000 but the money is almost all gone and there is still no cure in sight. The monthly costs of Elyse's medicine are crippling but there is no alternative.
The family has been buoyed by the support of the community, well-wishers and donors and Casey's friend Victoria Beacock, who has driven the fundraising, says she will keep fighting.
"No parent of a child suffering any life threatening illness should have to pay tens of thousands of dollars just to keep their child alive," says Victoria. "My goal here is to raise enough money to cover the costs of Elyse's medicine until a cure is found."
Casey Johnson says while DIPG is reasonably rare, all but one of the other children diagnosed around the same time as Elyse, whether treated conventionally with radiation or not, have died. The Johnsons hope to be able to continue to raise enough money to keep Elyse alive and stable until a cure for DIPG can be found. The financial strain is immense and Casey admits she worries constantly.
"As soon as money's coming, it's going and we've got about $1200 left ... I can't stop now when it's working.
So far Victoria and others have organised a variety of fundraisers and are continuing to search for ideas to keep the money coming.
The latest is a concert headlined by dubstep artist Tiki Taane at Taupō's Great Lake Centre hall on July 28 with a range of local musicians in support. Tickets are for sale at Ticketek.
The Supporting Elyse Givealittle page is still live and accepting donations and there is a Facebook page, Supporting Elyse, with regular updates on her progress and account details for donations.