The patient was her 10-year-old son, Darcy, who, in the space of a weekend, had gone from being seriously ill to being fast-tracked for a bone-marrow transplant.

Life as she and her family had known it was over; they were now well into the world of illness, of hospitals, of teetering daily on a fragile, swaying bridge between life and death.

What had begun as a few innocuous nosebleeds the previous year had spiralled into three rare blood disorders, the final of which was pre-leukemia. It would be a two-year journey filled with misery, pain and terror, mainly for Darcy, but also for his mother, sister and stepfather.

But it was also a time filled with frustration and boredom for Darcy, who was isolated for long periods, alone in a hospital room, as his immune system struggled to recover from the relentless, aggressive and, ultimately, lifesaving treatment he was receiving.

Because what Darcy wanted, more than anything, was to go to school. To sit in a classroom, hang out with his friends, and learn about the world around him.

“Until it turned a corner, every day was a life-threatening, life and death situation,” Gilmour says.

“Having said that, even in those situations, a child is still able to play games. Sometimes they are asleep or too unwell, but a lot of the time, they actually still need entertainment and education.

“All he kept telling me was, he was just so devastated that he couldn’t see his friends, he was so devastated that he couldn’t go to school, and just contrast all of that against the terrifying medical treatments that were happening to him every day.”

Gilmour tried her best to get him get connected back to their local school in north Canberra while he was still in the Sydney Children’s Hospital. But, much to her bewilderment and frustration, she discovered there was nothing much the school could do to help Darcy.

The teachers, while compassionate, were ill-equipped to engage Darcy with what was happening in a classroom three hours away, and there were no resources, facilities or guidelines in place to help children who were kept away from school for long periods because of illness.

Eventually, Darcy recovered, in what Gilmour can only describe as a miracle, given the odds he had been facing.

Today, he’s a thriving 18-year-old, currently spending a gap year in Japan, but it’s not surprising that Gilmour’s voice still trembles as she recounts the lead-up to Darcy’s illness and subsequent recovery.

Sitting in her living room in Canberra’s northern suburbs, she says what she herself gained from the experience, other than an unwelcome but detailed knowledge of blood disorders and hospital jargon, was a determination to help other Australian children who were being denied an education through illness.

“I could not turn my back on those kids when I watched what they go through, when they want to be a part of their school day, and they want to see their friends,” she says.

“It’s our responsibility to save their lives, but it’s also our responsibility to make sure they have a childhood.”

She also realised that what might be regarded from a distance as a hodge-podge career in public service, publishing and international development had perfectly prepared her do something about it.

In 2012, as Darcy recuperated, Gilmour and two other mothers who had had children in long-term hospital care, founded Missing School, a charity devoted to keeping seriously sick kids connected to their regular schools.

Gilmour co-authored Australia’s first report on the issue, which received wide media attention and a statement of support from then-prime minister Malcolm Turnbull when it was published in 2015. It helped, she said, that Darcy, along with countless other children, had been treated in the hospital’s Turnbull Ward, and that Turnbull himself was the country’s newly-minted leader keen for an easy-to-support platform.

Her work has been nationally and internationally recognised, and also earned her a nomination last year for ACT Australian of the Year, a turn of events that was in no way inevitable back in the days when when she left school at 15.

Born in the western suburbs in Sydney, Gilmour grew up surrounded by people of diverse backgrounds; her best friends were Lebanese, Italian, Chilean. Until she left home, she thought this was normal.

She also had a persistent stubborn streak, and while she was a straight-A student throughout high school, she decided to leave school after Year 10, much to the distress of her parents and teachers.

Her first job was in the public service, in the office of the then NSW health minister. Later, she worked for a contract publishing company, a job that soon her saw her, in her early 20s, travelling alone to London to set up an office and manage a publication for one of England’s biggest banks.

When she returned to Australia, she joined a small economic consultancy working in international development, in what would become a defining moment in her career.

“Very early on, I knew that this just really spoke to me and my values in terms of feeling good about what I was doing every day, getting up and going to work,” she says.

She couldn’t have known it at the time, but this work - reading reports, writing bids - would be the perfect training for when the time came for her to set up a charity that sorely needed funding. But that experience - those two years of terror and turmoil - were still years away.

She married and had Mia, now 22, and Darcy, both while completing a double degree - finally - in psychology and sociology. She also developed an interest, through her work, in global trends, another area that would later prove crucial.

She took a job with the University of Wollongong’s private company, which was working in international development, and stayed there for nine years. Her first marriage ended during that time, and she was eventually head-hunted by consultancy Hassall & Associates (later subsumed by GHD), and the family moved to Canberra.

That was in 2008. Just a year later, Darcy became ill. Gilmour eventually took two years off, from 2010 to 2012, to be his full-time carer. The family - including Hugh, Gilmour’s new husband of just two years - relocated to Sydney while Darcy underwent treatment.

Of course, despite Darcy’s isolation, and the general wretchedness of the situation, Gilmour was never alone, both during the ordeal and since. And since launching Missing School, countless people, both friends and strangers have come on board to tackle what is an emerging issue.

According the Missing School report, In any given year around 60,000 kids in Australia miss school because of illness, often for long periods. At the same time, breakthroughs in medical science mean more and more sick children survive, and leave hospital.

“The side effects are huge for the individual through this trauma, and without their education, without the social connections, that’s exacerbated. It’s really what it’s about - wellbeing,” she says.

“And then we look at the cost to society...what’s going to happen when these children grow into adults and they can’t become productive members of society because they’ve missed so much school? After we’ve invested in saving these human beings?"

Gilmour has hit upon a complex, multi-layered issue that is much more than just caring for sick children. In setting up the charity, she and her co-founders quickly discovered that not only were there no answers to their many questions, but that most of the questions had never been asked in the first place. There is no solid data about the numbers of children missing school through illness, and the effect both on them, and society, of this often prolonged lack of social connection.

“This is the main thing that I would have loved to have come out of the work in the Australia Day [ACT Australian of the Year] nomination,” she says.

“It was ‘Oh, a mum’s doing something nice to help sick kids connect to school’, but it’s a little bit more than that. This is actually a right, it’s in our legislation around equity, it’s in our anti-discrimination legislation, it’s been an invisible issue, states and territories haven’t been addressing it, really, not at scale.”

When she discovered tele-presence robots - devices that can live in the regular classrooms of students and be operated and moved in real time by the student from home or the hospital - she knew she’d hit on a solution.

“Two-way digital connection is the only way that you can solve this at scale, and that’s because it’s very hard for schools to deliver a scaleable connection if you’re not on location,” she says.

One day, she hopes these robots can be as ubiquitous in schools as wheelchair ramps. But schools and governments need to be on board first.

“I would love people to understand that this is an emerging issue, it’s not going away, and the technology and all of things are there that we need to make this happen are there, it just needs to happen at scale.

“We need to get consensus around what those elements need to be, and then it is the role of governments to make sure - it can’t be left to charity or chance, that’s not going to work.”

“I just want people to know that if you have insights that no one else has, and skills that match the change process that can happen, you just need to stick at it, because the lived experience is so powerful in driving that change,” she says.

“It’s more powerful than anything. I experienced a moral injury in that experience, and that moral injury came from all of my worldview, all of my experience, everything.”