No - you don't indicate that the child is disabled.
For a child under the age of 19, the "disabled" status has no effect on your tax return. Once they are 13 or older, the "disabled" status will help you with the daycare expenses and credits. Once older and if still "disabled", you will be able to claim the child as dependent without having to meet other qualifications.
To really be disabled, per IRS rules:
- the child cannot engage in any substantial gainful activity because of a physical or mental condition,
- your doctor determines the condition has lasted or can be expected to last continuously for at least a year or can lead to death
