The family spent a full day at the hospital yesterday and after checking Vector notices they returned home thinking the power would be restored.
A Vector phone message had said the power would be back on at 7.30pm - however later the same day the mobile app updated and said the power would be back on at 6pm today.
By then they were already home, with Mason sound asleep, and the family faced a long night without heating.
"At 3am he woke up screaming," Watts said.
"It was only 11 degrees inside and we had to make the call to get out.
"It's not good when your sick child is shivering."
The family could not heat any milk for Mason, and his favourite ice-blocks were also out of the question because they had already melted.
Instead the family drove to Watts' Mt Eden office to warm up using a borrowed car seat for Mason as his remained locked in the garage behind the electronic door.
The family stayed there for several hours before returning to hospital for Mason's chemotherapy.
The ordeal left Cox, who is 23 weeks pregnant, "emotionally exhausted".
"She has been up all night worried about his temperature," Watts said.
Any slight change in his temperature could be a concern, he said.
"We're all running on about two hours sleep and are exhausted."
Poor communication from Vector had left people making uninformed decisions, Watts said.
"If they had communicated better we would have made a different decision.
"It's hard to deal with from a parent's perspective."
Watts said he was always mindful there were people who had it worse, and there would be people who were totally dependent on power for medical reasons.
The family have now made other arrangements about where they will stay.
According to Vector, power in Titirangi might be restored by the end of tomorrow at the earliest.
Vector chief networks officer Andre Botha said he wanted to apologise for the situation this family, and others with medical needs, were in.
"We do our best to provide accurate estimates for restoration of power, but the scale of the storm on Tuesday night has made this task extremely difficult."
They encouraged anyone with medical dependencies to inform their power provider, he said.
"I want to reiterate our appreciation for the understanding, patience and resilience of those Aucklanders still without power.
"We are making good progress and hope to have all power restored soon."
According to Vector power could be expected to return to network feeders and substations which supply power to large groups of homes or buildings first.
Then it would be restored to critical infrastructure and buildings like hospitals, water and sewage plants, and airports.
The third priority was then large commercial buildings and industrial plants followed by residential and individual homes.
Finally, power would be restored to streetlights and hot water pilot lines.
A Mercury Energy spokesperson said it encouraged any medically dependent or vulnerable customers without power to stay with friends or family, go to the hospital or contact 111 if there was an emergency.
"We understand the challenges faced by a large number of people impacted by the storm and we know Vector is working hard to restore power as soon as possible.
"We particularly feel for this family, and having been made aware of their circumstances and spoken to them it's great to hear that they have a plan in place."
