Ashya King's brother Naveed said in a new video blog posted on YouTube that the family had not "neglected" the five-year-old.
He said that footage released yesterday showing his father and his brother had been filmed minutes before the police arrived.
He also claimed that reports that his parents had been arrested while driving the family car where inaccurate.
According to the 20-year-old, the family were spotted together while filming a video of Ashya.
"He was obviously happy, he wasn't in any way in any danger and he was not neglected at all," Naveed said.
Referring to concerns expressed by Hampshire police over the machine used to feed Ashya, Naveed held up packages of food to the camera and said the family had bought a "box load".
He also said that the family had purchased a brand new wheelchair costing up to £1,600.
Ashya King's parents told the Daily Mail they fled the UK after being told NHS treatments would leave him with life-long disabilities.
The head of the police force which applied for a European Arrest warrant against the parents of Ashya King has now urged their release.
A British mother whose son's life was saved by proton therapy has told ITV that she defied NHS doctors' advice to pursue the treatment.