They said their fight to find him did not end when British police ruled he died in an accident the day he vanished on the Greek island of Kos in 1991 aged 21 months.
In a message on the official Help Find Ben Needham page, the family said they had to accept the most heartbreaking news that he “would not be coming home”.
But they begged anyone who knows where he is buried to come forward.
“Somebody out there knows something,” they wrote.
PA / PETER BYRNEACCEPTANCE: Ben Needham's family said they have to accept that their son won't be coming home
GETTY26 YEARS: The search for Ben Needham has lasted since 1991
“Someone took him away from me”Kerry Needham
“You may not think it as important.
"It could have just been a flippant comment made by someone.
“But any piece of information could be vital in finding Ben and bringing him home to rest.”
Five months ago, his mum Kerry was told it was likely Ben died in an accident with a digger driven by local labourer Konstantinos Barkas, who has himself since died.
GETTYHOME: Ben's family pleaded to be able to bring his body home
On what would have been Ben’s 28th birthday five weeks ago, Kerry, from Sheffield, wrote on Facebook:
“Someone took him away from me.
"Please do the right thing and tell me where he is please.’’
The Facebook page adds: “Please do not let 2018 be another year without Ben home.’’