"I was thinking as we were driving over there maybe it's not. Maybe we'll retake the bloods and it will be alright sort of thing," Davis said.
"When we got there they explained everything and told us and that they couldn't give a definite diagnosis of what type until he had his bone marrow operation."
Reuben was in and out of hospital within a week, but now has regular visits to hospital and has developed steroid-induced diabetes as a result of his condition.
He needs two or three injections a day, but his phobia of needles can make the process and his treatments difficult, Davis explained.
Davis said it will be a long road ahead for Reuben and their family, but things are looking good.
"The doctors have told me that they don't suspect it will be a long time thing.
"All the time the treatments are getting better and the statistics are pretty good," she said.
Through the help of family, friends and their local church, the family is getting through.
Davis has taken time off from her work at North Shore Hospital to care for Reuben.
One of her colleagues and friends created a Givealittle page, with all the money raised going towards the family.
Davis was surprised when her friend created the page, but was grateful.
"I have friends back home in Ireland and my friend said people just want to help out and it is just one way people can.
"He also would have been starting Year 7 this year but he won't be able to go now, so we thought we could use some extra money to help with some education," she said.