Ms Lang said she had been told by Starship Hospital and the doctors to expect him to get ill and require isolation, "but by some miracle he has not required isolation at all this year".
"That has been amazing. We have had ups and downs but in terms of what we expected it has been good."
She said one of the biggest achievements was Asante managing his first full year at school, and the growth which had come with that.
"He's come a majorly long way."
Ms Lang said because they had only just moved to Rotorua when Asante was diagnosed, he hadn't had the chance to make friends.
"Now he's made a really cool, like, network of friends and he's been playing Rippa Rugby. I think those have been the two facts that have carried him through so well."
He was awarded the club sportsman of the year at St Michael's Rugby and Sports Club junior prizegiving.
Ms Lang said she had massive apprehension ahead of sending him to school and relinquishing the semi-control they had over his health, but it had been worth it.
"It has blown me away. It has been about trusting my instincts and letting him have [a] semi-normal life as much as possible."
She said the teacher had commented at the end of the year that she couldn't believe the confidence Asante had developed.
"He's handled it really well. He's like a different kid."
Ms Lang said while they still had to take it one day at a time, and she was aware things could change, she was pleased with his progress. He's still in the maintenance phase of treatment.
"His health has been amazing."
She said they had a few ups and downs, and a few issues with his medicines.
The family was still dealing with the side effects from Asante's chemotherapy including struggles with eating.
"He went off meat for about four to five months until his coaches at Rippa Rugby managed to bribe him."
But, after the horrible year of 2015 when they almost lost their boy, 2016 was better.
"He's not out of the woods, we've still got 18 months to go."
He still has restrictions - he has to stay away from crowds and isn't allowed in confined spaces with lots of people like movie theatres - but Ms Lang said she believed those restrictions helped prevent him from getting sick.
She said over the past three or four months he had issues with pain after chemotherapy, something doctors put down to his body getting "over it" after two years.
"We take it day by day."
