Neon Roberts is back receiving emergency medical treatment after a frantic week in which he and his mother were the focus of a nationwide search in the UK.
Neon, 7, who recently had surgery for a brain tumour, was described as a "very sick little boy", in desperate need of radiotherapy treatment.
But his mother, 37-year-old UK woman Sally Roberts, believed it would damage his growth, hormones and intelligence, so she allegedly ran away with him to give him "natural remedies".
The story made headlines after a judge made the rare move to reveal Neon's identity, in fear he could die if he was not treated.
In making the ruling to permit the identification of Neon, Justice Mary Hogg had urged Mrs Roberts to come forward.
"...The doctors say that, unless treatment is started next week, the prospects of Neon surviving are dramatically reduced. I have asked for the assistance of the public in looking for this very sick little boy."
"He suffers from a brain tumour and has recently had surgery and the doctors responsible for his treatment believe he urgently needs radiotherapy," Justice Hogg said.
Search for Neon
The story of Neon was picked up by major UK outlets including The Mirror, the Telegraph, the BBC and The Independent.
The mother and son went missing from Tiverton, in Devon, on Sunday. Three days later they were found in Sussex, more than 250 kilometres away.
Neon is now in foster care.
A statement issued by the police force on Wednesday said: "Following extensive press coverage... the high risk missing person, seven-year-old, Neon Roberts has been located by police officers in Sussex.
"Emergency protection care has been put in place and Neon's welfare will be considered in the High Court.
"Devon and Cornwall Police would like to thank the public, the media and police colleagues in Sussex for their assistance in securing Neon's safe recovery."
When their disappearance was revealed to reporters, Neon's father Ben Roberts said his estranged wife was worried about what radiation would do to their son.
"She wants to do everything she can and rely on natural remedies and things that are not too invasive, rather than radiotherapy and chemotherapy," Mr Roberts said, according to the Daily Mail.
"She is worried about the damage that can be done. She wants him to be able to live a normal life.
"Personally, I want everything for him. I want to make sure he has everything available to him.
"I understand there are lots of things that can be done to minimise the after-effects of radiotherapy, with various other pre- and post-treatments.
"All the evidence I have been presented with has told me he needs to have that therapy, but I am also aware there are side effects. It concerns me as well."
Last week, an Australian judge ordered a couple to immunise their eight-year-old girl after the mother had tried to prevent the father and his partner doing so.
The mother made the application after discovering that her daughter's stepmother had secretly taken the child to a medical centre to have her immunised against diphtheria, tetanus, pertussis, hepatitis B, polio, HIB, measles, mumps, rubella and meningococcal C.
Previously, the mother had been arranging homeopathic vaccines.
She told the court she adhered to a "simple and healthy way of life", that included eating organic food, using non-toxic cleaning products and sending the child to a Rudolph Steiner school where the toys were made from natural products such as wool, wax and silk.