The dreaded school run is a daily battle for most parents. Even once out of the door and at the school gates, feigned smiles and small talk with other haggard parents can be a mass performance. For Stuart Green, who spent years wrestling his young twins out of car seats and into coats, all the while keeping an eye on his eldest daughter, it was the small talk he dreaded.

“Is Mummy at work?” someone might ask. Green’s response would be a half truth: “I’m a single parent.” The full story could not be explained in a 15-second conversation on the street.

Green’s wife, Mia Mascariñas-Green, was murdered nearly a decade ago in the Philippines when two gunmen unloaded close to 30 bullets into her family car. Her three children were in the back seat. The Filipina human and environmental rights lawyer had no chance. Nine bullets hit her head and neck.

Somehow, the twins, who were less than two at the time, and their older sister, who was 10, escaped unharmed. The family nanny, also in the car, survived. Green, who is British, describes his children as “walking, breathing, laughing miracles”.

Having settled back in the UK, Green has spent years worrying that he and his family would be “defined by tragedy”. And if someone is reduced to the top results from a Google search of their name, then Green might appear to be an eternally grieving father in shock.

Now he is ready to retell his story exactly the way he wants to – reframed from a negative light to a positive one.

Green’s book, The Regenerate Leap, is being published this month. It offers advice to others who need to forge a path through a traumatic crisis – not only to survive but thrive.

A marine biologist with a career in sustainability-focused consulting, his book is not just for parents but for anyone in a leadership role, whether that be in a family, a business or a community. In the opening chapter, Green calls his book “the manual I could not find”.

In the aftermath of the killing, he read books on grief and trauma but grew frustrated with the focus on “inner strength”.

“In all the literature, it’s about being strong and resilient, and seeing your way through,” he says. That, he concluded, was not possible for his family – they had lost a wife, a mother, a home, their dogs, a whole life in a beloved country. “It was a wipeout,” he says. “So there is no resilience.”

Still, Green did find one thing in those books, which scared rather than consoled him. It was the concept of intergenerational trauma, passed down from parents to children. “I realised that the children would be carrying on the narrative,” he says.

The core idea of the book is the concept of “regeneration”, which he writes, is “not the absence of pain” but “transforming your pain into your purpose”.

The book’s central metaphor is the pine cone that releases its seeds only under the intense heat of a forest fire. Green argues that crises can “crack us open” to release dormant strengths.

“I’m not saying the devastation is good,” he writes. The philosophy is to honestly acknowledge the loss, then to use the crisis as a catalyst to grow into something that could never have existed without the “fire”.

When his children were very young, Green held back on details of the attack. Today, they know the whole truth but, as the book says, it gave them an “empowering truth”: that “their mother died fighting for justice, and they carry her courage forward”.

He points to his eldest daughter, Grace Sr. He says her therapist described her as having grown from a “traumatised teenager into a young woman of remarkable wisdom, purpose and capability”.

Surviving a crisis left her with exceptional strength – when she was 10 she testified in court over the murder of her mother and attempted murder of her and her younger siblings.

The case is continuing in the Philippines, with one person detained and another at large.

Now 18, Grace Sr plans to become a lawyer, like her mother. It was her idea to write the book to help others, and the father and daughter spent last summer editing the stories together to make sure it was readable for young people affected by life’s inevitable horrors.

“It’s not about changing the facts, those remain the same,” Green writes. “It’s about deciding what those facts mean for who you’re becoming and where you’re going.”

Writing has helped the family’s regeneration, says Green. “The most profound reframe is the shift from victim to author; from someone to whom things happen to someone who chooses what those things mean and what comes next,” he writes.

Reflecting on the past eight years, Green says he needs to “flip the narrative”, to “take this horrible situation and make it as positive as it can be”.

Is he nervous about the extra attention that publishing this book will lead to, and more probing questions on the school run? Absolutely, but Green is accepting of it.

“I guess in another way, it’s for me to just also challenge myself to embrace that this is my reality,” he says. “This is my way to share it.”

• The Regenerate Leap is published on 28 January