I watched tremulously as my fiancé, Alan, steadied himself and his camera on a craggy edge of the Cliffs of Moher, facing the wild Irish waters. Through the torrent of rain and gusts, all I could think was ‘please don’t fall in’. We had caravanned from the nearby village of Doolin alongside a crew of friends for a rehearsal. The next day, in the same location, 24 of us would bear witness as our friend Gary fulfilled his beloved’s final wish: to scatter her ashes in the sea.

At the cliffs, the panorama astounded. When I looked one way, gilded light surged from the sky. From the opposite direction, a looming shroud of grey unspooled. Soon rain pelted our shoulders and sides, followed by a rainbow. Phillip, a local artist, tipped up his chin. “The beauty of this weather is its changeability.”

“Just like grief,” I added. In my 37 years of life, I’ve been sideswiped by grief’s terror and its majesty. But this Ireland trip was not about me.

Her name was Allison Wilke, but she often chose to go by Allison W Gryphon, inspired by the mythological creature which symbolises courage and strength. I’d only met Allison once. On that bright Los Angeles afternoon in 2015, she visited my apartment to discuss a film project with Alan. They’d collaborated for years, and at the time of her passing, she was working as a producer on the Netflix show The OA. After the final episode of season one, the screen goes black and the message ‘In Memory of Allison Wilke’ appears.

As we sat around the table four years ago, Allison told me she yearned to return to Doolin where she’d stayed for six weeks during a writing retreat 11 years ago. She hoped to continue her work there on a series of novels. I told her I couldn’t wait to see her dream come true.

You may also be interested in:

• When everything falls away

• A deadly predator that brought solace

• Ireland’s secret to a low-key life

Allison’s first cancer diagnosis was in 2011 when she was just 38 years old. At the time, she and Alan were casting roles for a project they planned to start shooting soon. Instead, both decided to scrap that and make a documentary about Allison’s fight against cancer. In the film, you see Allison in the operating room, moments before her mastectomy; and again post breast-reconstruction surgery, as a tattoo artist etches triumphant ink wings on her. You see her driving home from the doctor, windows rolled down and smiling, on the day she finds out she’s beaten the first round of her disease.

Allison released the documentary in 2014 and started a foundation to help others fighting cancer. But just two years later, from a hospital bed, she’d tell her partner, family and closest friends she was dying, followed by, “Everything will be OK.” In her final days, she requested they take her ashes to Doolin, where she envisioned herself at peace.

Two years after her death, here I was in Doolin, the place she longed to see again – but without her. How cruel it seemed. I felt unworthy: undeserving to be present alongside people like her partner Gary, with whom she’d exchanged hundreds of handwritten love notes; her father Doug, who had known her as a sunny-haired child; or her friend Alia, who did Allison’s laundry when she found it too difficult to lift her arms.

I wasn’t Alan, who’d combed through more than 100 hours of Allison’s documentary footage when she was still alive, because she couldn’t bear to do it herself. At the time, Allison had just completed her chemo treatments and her hair had grown back. She was not ready to relive the most frightening parts of her battle.

If someone can think of something – anything – you can do to help them reshape their life, it is a gift

Nor was I Phillip, who runs an art gallery in the nearby seaside town of Lahinch, who joked to his wife on the day he met Allison 11 years ago that he’d invited a ‘California blonde bombshell’ home as their dinner guest. Their friendship stuck. During Allison’s cancer battle, Phillip placed a picture of her in good health at one of her favourite spots: the mythic shrine of St Brigid’s Well in County Clare, whose water is believed to have healing powers. Pilgrims often leave photos and keepsakes of their sick or departed loved ones in the damp cavern. Phillip had sent Allison a photo of herself among the tapestry of totems – a reminder that Allison’s Ireland was with her, beckoning her to mend.

Among those who mattered most to Allison, I was merely a tangential part of her life. But Alan told me he needed me to come. As a funeral singer for more than two decades, I’ve learned not to hesitate when a grieving person requests your presence. Through the pain of reckoning with the loss carved in our hearts, if someone can think of something – anything – you can do to help them reshape their life, it is a gift.

After her death, two of Allison’s friends unexpectedly found footage she shot of herself talking into the camera. Some of the footage was fragments of a video diary from Allison’s time in Ireland years earlier, and some was from her cancer battle that wasn’t used in her documentary. The plan was for 24 of Allison’s closest friends and family to film each other whenever we felt inspired and to record interviews about Allison for a new movie about grief. Just as Allison had leveraged the camera to make art out of her suffering, so would we. As we landed at Dublin Airport, Alan handed me his digital camera.

The journey was for the mourners just as much as it was for Allison. It was a motion to heal, to remember her joyfully and to smile again, as Allison would have wished. During our week-long trip, we gleaned clues from Allison’s old photos, footage and stories to retrace her steps – from the Well to the Cliffs to the corner booth at Fitz’s Pub & Eatery in Doolin, where she wrote her first manuscript.

During her time in Ireland, Allison wrote about witchcraft and spells. She visited Irish fairy trails in forests dotted with miniature houses rumoured to be inhabited by spirits. Years later, after Allison met Gary, she devised an elaborate story about fairies for his two young daughters, and left letters and whimsical evidence to keep them enchanted, even after her death. In Allison’s honour, we hiked in the driving rain and mud to visit a local fairy trail. We discovered mini cottages and tiny clotheslines gracing the grounds of an 18th-Century mansion, the Falls Hotel & Spa.

At our group dinners at Fitz’s, I listened to other people’s stories about Allison. Her aunt Agnes’ sky-blue eyes teared up as she told me that Allison put others first, even while ill. Her 86-year-old father spoke with his Long Island accent about their summers sailing together. With each memory shared by those who loved her, I became a witness, a keeper, of parts of Allison’s life, and I vowed not to forget them.

In the Cambridge Dictionary, a definition of the verb ‘witness’ is a command: ‘Be the person who sees’. Here I was, living, breathing evidence that someone I barely knew had loved well.

Here I was, living, breathing evidence that someone I barely knew had loved well

By the time Gary asked me to join him in the private bar at Hotel Doolin, where he would film his interview about Allison, my feeling of unworthiness had faded. He had summoned me as his witness. I’d felt a similar pang of honour when a father had asked me to sing Danny Boy at his young son’s funeral, entrusting me with his grief; and when a teacher in high school requested I rehearse a hymn with her – a song I would sing at her funeral months later.

I asked Gary why he wanted me there when he could have chosen someone who knew him and Allison better. He told me I understood the grieving process and the magic Allison brought – and still brings – to him. Earlier that week, Gary had confided that he believed Allison had visited him through signs, some as bewitching as when he’d stumble upon a fairy door. Perhaps he detected that, like Allison, I was open to magic and would believe him.

Alan perched the camera on a tripod in front of Gary. I sat on a bench off to the side. When Gary spoke about what it was like to sit beside the woman he loved as she left her physical life, Alan looked over at me. He knew my biggest fear was to lose him. And yet, I felt something tell me this wasn’t the end for Allison, that there’s no end for any of us, as long as there are witnesses.

On the final night, while I ate fried cod and brown bread at Fitz’s, Allison’s closest friend, Mary Beth, asked me to be her ‘eyeline’ during her interview. I’ve worked in film and television and I’ve stood on the receiving end of another’s gaze. But not like this. Not to someone grieving. But Mary Beth reassured me. She said it felt natural to her for me, a warm force, to be her point of focus while she faced her grief.

When the camera rolled, Mary Beth told me that when things felt unbearable, when life was ‘bats’, as Allison had called it, she encouraged her to turn a negative situation into butterflies. And then one day, to Mary Beth’s surprise, Allison said to her: “You did it. You’re becoming a butterfly”.

The 24 of us drew close as Gary scattered Allison’s ashes off the Cliffs of Moher. We put our arms around each other, many of us strangers until this trip. That cavernous void we call grief can be dark, and can be heavy enough to crush us. But when there are witnesses – people who see us – it can feel light and lucent instead. When I watched Gary kneel on a promontory and joggle the urn towards the sea, I knew the shape of him would change to accommodate the loss of her. I could already detect his morphing, his butterflying.

That morning we said goodbye – the morning we brought Allison home – the cliffs, the sea, the day were all our witnesses. I had become a griever by then, one of them. Now that you’ve heard Allison’s story, you are, too.

Our tears fell like rain, but the Irish sky, ever-changing and miraculous, was a clear cascade of sun. And we were all there to see it.

This article was published with permission from Gary Rizzo.

Travel Journeys is a BBC Travel series exploring travellers’ inner journeys of transformation and growth as they experience the world.

Join more than three million BBC Travel fans by liking us on Facebook, or follow us on Twitter and Instagram.

If you liked this story, sign up for the weekly bbc.com features newsletter called "If You Only Read 6 Things This Week". A handpicked selection of stories from BBC Future, Culture, Capital and Travel, delivered to your inbox every Friday.