The devastated grandmother of little Ashya King today urged his parents to 'bring him back', over 24 hours since they were last seen.
Patricia King, Brett King's mother, said her grandson had recently been showing signs of improvement.
His health had picked up and he was even beginning to smile and move his limbs, she said at her home in Portsmouth.
And she revealed the youngster had first gone in for treatment on the cancer a month ago after doctors originally diagnosed his illness as arthritis.
Tearful Patricia, wearing a black cardigan, navy jeans and blue sandals, said: "All I would say to Brett is please, bring him back.
"Everyone is looking for him but I don't really know the situation - the police are yet to tell me anything.
"We have all been in a terrible state over Ashya's health - it's been a dreadful time for us all over the last month.
"But I suppose it's up to my son where he takes him - I'm just Ashya's grandmother.
"He's recently got a lot better - he's moving his arms and legs and is beginning to smile and notice the people around him.
"We were all getting more hopeful lately but when the news first broke it was devastating.
"Ashya's been in hospital a month after the doctors told him he had arthritis but it turned out to be a dreadful tumour.
"I thought they were at the hospital - I had no idea they had gone anywhere until this afternoon.
"When I heard I thought the people were going to tell me worse news - that he had died already or something.
"I haven't been in contact with Brett and I don't know anything about them running off to France.
"I've no idea why they've gone there - they don't even like France.
"They certainly wouldn't take him away on holiday in his current condition and I doubt Brett would try to get in contact with me now."
But she said the couple do not have a holiday home in Spain, so could not shed light on where the family were heading.
Patricia (above) added: "Brett is a wonderful caring father and his kids love him. Ashya is the second youngest of them all.
"As for Naghemeh - she's been by Ashya's side the whole time, sleeping by him as she doesn't work and cares for the children."