In the secret garden why is Colin locked in the bedroom?

In "The Secret Garden," Colin Craven is locked in his bedroom due to his father's overprotective nature and fear of his son’s health. After the death of Colin's mother, Mr. Craven becomes emotionally withdrawn and believes that keeping Colin isolated will prevent further distress. Colin has been led to believe that he is disabled and will never walk, which contributes to his seclusion and negative mindset. This confinement is a key element that drives the narrative of healing and transformation through the discovery of the secret garden.