However, Mr Casey said the toughest thing for the family is transition.
He said Charlize doesn't like change.
"It's tough getting her to school but once she gets there she really enjoys it."
When the family first started looking for schools, they felt uneasy about their local school because Charlize has a tendency to run away when she is unsettled and the school is on a busy road.
At the time, the Caseys lived across the road from Morningside Primary deputy principal and special needs co-ordinator David van de Klundert.
Charlize started at Morningside Primary in February 2015.
Middle daughter Raven screams when she is anxious.
The family moved to a lifestyle block at Mt Tiger where they don't have to worry about upsetting the neighbours.
With this move, the girls started at Glenbervie School this year and are making good progress.
At school, as well as a teacher aide, the girls spend four hours each a week with a specialist.
"They both respond to one on one teaching better."
Youngest daughter Piper, reacts differently again.
"When she turned 2 she stopped talking and didn't say anything for about a year."
Education is key for the Caseys, and they know they will have to go through similar transitions for high school and employment.
"It is really critical, it is proven beyond doubt they will perform better at mainstream school."
It's not just school, Mr Casey said even a transition as simple as getting them to go to bed can be tough.
"We went through six months of hell when nobody was settling."
"They're not being naughty kids, they're not throwing things or being disruptive."
Mr Casey said it goes in waves of different behavioural issues.
"Sometimes it's better to compromise, sometimes it's better to actually fight the battle."
Mr Casey has a message for others who have children with autism.
"Don't be afraid to ask questions. Ask parents what it's like. Approach it friendly, it's not a bad thing, it's not a behavioural thing.''
For more information about autism go to www.autismnz.org.nz, ring Phone: 0800 AUTISM (0800 288 476) or email the Northland branch of Autism NZ at northernhub@autismnz.org.nz.