Joe Altberg last saw his parents as they waved him off on a train leaving Vienna in 1939.
Joe, who later changed his surname to Allan, learnt of his father's death at Buchenwald in 1940 through the Red Cross, but his mother's fate remained a mystery - until recently.
With no knowledge of when or how she died, he has never lit a yahrzeit candle or been able to place a stone on her grave.
While Mr Allan, who came to Britain as a child refugee, has learnt to live with the unknown, the unanswered question has chipped away at his daughter Helen Levy.
Determined to uncover what happened to the paternal grandmother she never knew, 57-year-old Mrs Levy from New Malden, Surrey, said: "I squirreled away in the middle of the night looking for anything I could find about her."
I have no idea how my parents got me out of Poland
The only thing known about Henya Altberg, after whom Mrs Levy was named, was that she died in the Lodz Ghetto. After some research, it emerged that she had been deported from Austria to Poland, from where she originated.
In 2000, Mr Allan travelled to Lodz in an attempt to find out what happened to his mother. While there he visited the city's cemetery, where a local guide, who was well acquainted with the graveyard and the history of the ghetto, showed him an overgrown field.
This, he was told, was the mass grave where she was buried - but there was nothing to mark the exact location.
Mr Allan, who is 93 and lives in Nightingale House in south London where the walls are adorned with tapestries he himself has created, told the JC: "I have no idea how my parents got me out. They came to the station to say goodbye and that was the last time I saw them.
"The guide in Lodz showed me where my mother's house was before it was knocked down.
"Then he took me down to my mother's grave and it was just an open space - I couldn't see anything. He said, 'I'm sorry, that's the best I can do - she's buried somewhere in this ground'."
The search for his mother's final resting place seemed to have come to an end, until his daughter got involved, and stumbled across the work of the Lodz Jews Heritage Foundation while researching online.
"When you have lost three grandparents in the Holocaust, it leaves quite a hole," she said.
The foundation, a body set up more than 20 years ago to revive and preserve the city's Jewish heritage, runs a website enabling relatives of Holocaust victims to find their ancestors' graves.
"There's more and more information being put up all the time," Mrs Levy said.
"When I started researching what happened to my grandmother, I discovered there was actually a plan for the Lodz cemetery and my grandmother's name was on it, so I asked them to confirm."
The foundation, which is run by volunteers, tracked down the burial place and arranged for a headstone to be made and put in place.
Now, more than seven decades after Mrs Altberg's death, her grandaughter, herself a mother-of-three, is preparing to take Mr Allan to Poland for the unveiling of the headstone at the grave.
The pair hope to be accompanied by a carer who will look after Mr Allan.
"I have done what I can for my parents as far as I'm concerned - I've honoured them," he said.
To show the family's huge appreciation, Mrs Levy has launched an online fundraising campaign to support the foundation.
"I want to really make a difference to the foundation's work," she said.
"What happened to my grandparents is really important to me. I am named after Henya and so is my cousin Harriet in America. The stone we put on and the words we used are about saying we are still here."
She added: "I am inspired and given hope by this."
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