Is the presence of a disabled child considered a divine punishment for a specific sin, especially since many sinners are not afflicted with this, while devout people are?

Ibn Hajar mentioned in Fath al-Bari that Allah's testing of His servant in this world is not due to His wrath, but rather to avert an evil, atone for sins, or elevate status. If the servant accepts this with contentment, then his objective will be achieved. This is supported by the fact that trials can reach the most obedient of people, such as the Prophets. Therefore, it cannot be asserted that the disability of a son is a sign of Allah's wrath and punishment upon his father.