It was in mid-2014, 42 years after Keenan had left the central city of Da Nang. Sitting on a bench at a hospital in New York, U.S., with his biopsy results in hand, he realized that he, like many fellow veterans, had developed cancer.

That night Keenan searched for everything he could find about dioxin. The images and documents transported him back to memories of Vietnam four decades earlier.

In 1971 Matt was deployed in southern Vietnam, assigned to a unit responsible for personnel support and casualty reporting.

His job included recording casualty numbers and helping soldiers recover from drug addiction before returning home. The work exposed him to death and danger on a near-daily basis.

In Da Nang, he was stationed at a hilltop base where helicopters flew at eye level and the roar of Phantom F-4 fighter jets filled the air day and night. He lived alongside soldiers held on charges of killing civilians.

Many nights they became drunk, shouted and vandalized the place, leaving him unable to sleep. “Every day I counted down and marked my calendar, hoping to go home,” he recalls.

His last memory before leaving was on May 7, 1972, as he sat at Da Nang Air Base awaiting transfer to Saigon for discharge procedures.

A plane landed, and hundreds of women carrying babies poured out, barefoot and without belongings, having just fled fierce battles in the central cities of Quang Tri and Hue. “I was forced to leave with a heavy sense of guilt for what Americans had done to this land,” he says.

Three days later he landed in New York. His mother greeted him with a message taped to the front door that read: “Love, peace and happiness.” But the war had changed him permanently. “I tried to deny and suppress the trauma, but over time, the memories began to surface like the fizz when you open a soda can,” he says.

The war left him haunted. He became terrified of ceiling fans, whose whirring reminded him of helicopters in Da Nang.

Loud noises from behind startled him, and he often dreamt of military funerals, firing 31-gun salutes, playing the bugle for fallen soldiers and folding flags for grieving widows.

Struggling with both emotional and physical scars, he sought treatment and was diagnosed with post-traumatic stress disorder, or what many Americans referred to at the time as the “Vietnam syndrome.”

He describes the pain not as a singular memory but as a build-up of jet engine roars, helicopter blades, missile launches, casualty reports, death tolls, and a profound sense of loneliness.

In 2012 Matt retired. Two years later he was diagnosed with cancer. “I was shocked to learn that several generations of Vietnamese people were also exposed to Agent Orange,” he says. “Vietnam had never been a place I wanted to return to, not even for a holiday, but this discovery stirred something in me.”

A few days later he wrote to the Vietnam Friendship Village, a center supporting Agent Orange victims, and Veterans for Peace, a U.S. group promoting peace and reconciliation, expressing his desire to return.

In mid-2015 he arrived in Hanoi, carrying with him fears of how Vietnamese people might treat an American veteran.

Matthew plays football with children at the DAVA center in Hai Chau District, Da Nang. Photo courtesy of Matthew

Friends back home found his decision hard to understand. But Vietnam was not what he had imagined. He stayed at Peace House in Tay Ho District, a residence for volunteer English teachers. Locals greeted the white-haired, blue-eyed “Tay” (foreigner) with curiosity and warmth, often stopping to chat.

Four days later he traveled south to Da Nang, where he visited a center supporting children affected by Agent Orange. Children with deformed limbs crawled toward him, laughing and wrapping their arms around him.

He joined them in painting, beading and playing basketball. That moment transformed what he thought would be a one-time visit into the beginning of a deeper connection. Three months later he returned to volunteer at the Da Nang Association for Victims of Agent Orange (DAVA).

There, he met Phuong, a boy affected by dioxin exposure who had dropped out of school in second grade and survived by doing odd jobs. Matt, towering over Phuong in size, recognized a shared bond, they both carried the same invisible burden.

“My disease is hidden inside, but Phuong’s is visible. His life is tough, yet he has never given up,” he says. “He became a huge source of motivation for me.”

Each day Matt drove 20 km to DAVA facilities, helping children learn English, do crafts, play sports, and simply enjoy being children.

Matthew meets fellow veterans at Truong Son National Martyrs Cemetery in Gio Linh District, Quang Tri Province. Photo courtesy of Matthew

Every four months he returned to New York for cancer treatment. “The closer I grew to them, the more I healed,” he says. Around the children, he no longer felt like a man nearing 80. Their laughter brought out his playful side, and he was willing to act silly just to make them smile.

Using his pension, he bought cakes, milk and bicycles to brighten their days. By mid-2018, after seeing the children crammed into a small truck on their way to school, he launched the Safe Bus for Kids project, successfully raising funds for a 29-seat bus.

He continued to advocate for more support, helping fund a basketball court, tables, chairs, and swings. At Christmas in 2019, he decided it was time to stop “ping-ponging” between the U.S. and Vietnam. He sold everything he owned in New York and moved permanently to Son Tra District, Da Nang. The move happened within just a few weeks, right before the Covid pandemic began.

In 2020, he married Yen Lan. Together, they devoted themselves to charity work supporting children affected by Agent Orange. Now he spends much of his time traveling across Vietnam.

During a trip to the Truong Son National Cemetery in Gio Linh District, Quang Tri Province, in 2018, he encountered a group of Vietnamese veterans paying their respects, lighting incense and laying flowers at the graves.

Matt sat on a stone bench, talking with a Vietnamese veteran about the war more than 40 years ago. Before they parted ways, they shook hands. “The war has long passed, and the wounds are healing,” he says.