A woman, two men and a teenage girl were arrested on suspicion of neglecting Liam Shackleton, who fell from the window of a flat in Leeds.
Social workers were not involved with the family, but the city's Safeguarding Children Board said it planned to oversee a review of Tuesday's accident.
Neighbours said Liam had moved into the flat in Lindsey Mount recently along with his parents, two brothers and sister. It is understood Mr Shackleton's father was the tenant of the property.
Mr Shackleton told ITV News that Liam had ADHD (attention deficit hyperactivity disorder).