A woman whose seven-year-old son has undergone surgery on a brain tumour is trying to persuade a High Court judge not to allow doctors to treat him with radiotherapy.
Sally Roberts, 37, who is living in Brighton, East Sussex, said she was not a "bonkers mother" and feared that radiotherapy could do long-term harm to her son, Neon.
But doctors said Neon might die within months without radiotherapy treatment.
Mr Justice Bodey was hearing evidence from both sides at a hearing in the Family Division of the High Court in London.
He said neither any hospital where Neon received treatment nor any medic involved should be identified in reports.
The judge - who heard that Ms Roberts' estranged husband, Ben, had consented to radiotherapy - said Neon's condition was the "stuff of every parent's nightmare".
He said he would balance what radiotherapy treatment would achieve against the "downsides" before making a decision.
The case hit the headlines earlier this week when Ms Roberts, who was then living in Tiverton, Devon, disappeared with Neon. Both were found safe after a judge ordered a search.
Ms Roberts, a New Zealander, on Friday apologised for vanishing and told Mr Justice Bodey that she had "panicked".
Mr Justice Bodey said he would announce his decision on radiotherapy on Saturday.