His death certificate from Kinrara British Military Hospital, Malaysia, blames hydrocephalus (water in the brain) for the 3-and-a-half-month-old's death.
His father, also called Desmond, was deployed to Borneo soon after his family's traumatic loss, leaving Helen to process it, while caring for Renata, 5, Ruapeka, 3, and Michelle, 2.
She spent the rest of her life yearning for baby Desmond.
It led to episodes of depression and hospitalisations in Lake Alice and Sunnyside mental institutions, and electric shock treatment.
But in her final years, Helen heard comforting news from Ruapeka at her bedside.
There was growing support for the repatriation of servicemen buried in foreign cemeteries, and this would include baby Desmond, subject to her consent.
"I can quite clearly see the expression on her frail face of pure joy, followed by a look of resigned relief and a long pause - like a moment of reflection. 'That would be very nice son.'"
In May, Ruapeka flew to Cheras Rd Cemetery, Kuala Lumpur, "to tell Desmond he would be coming home shortly".
It has now been 24 days since baby Desmond landed in Auckland International Airport, as part of the Te Auraki project.
You couldn't miss the startling white wooden panels enclosing his remains, among 27 much larger caskets, draped in navy blue New Zealand flags.
Ruapeka accompanied his baby brother in the Osbornes' hearse back to Rotorua; the Rogers' hometown.
Desmond and Helen's kids spent every school holiday "playing around and catching up" with their cousins there, during their father's military career, going from camp to camp.
His marae was Ōwhata Marae at Hinemoa Pt and Ruapeka got married there 35 years ago.
The hearse took baby Desmond back to the family home in Fenton Park, where he spent the night before a private funeral service and cremation was held for the Rogers whānau the next morning.
Baby Desmond's urn now takes its rightful place on the prayer table in the family home, next to his mother's and father's.