My son was legally disabled until August 2019 (last ssi payment received), would i put he was disabled on tax forms or select none of the above?

[Bsch4477]

A person is permanently and totally disabledif both of the following apply. 1. He or she can't engage in any substantial gainful activity because of a physical or mental condition. 2. A physician determines that the disability has lasted or can be expected to last continuously for at least a year or can lead to death. 

From your post, he would not be considered disabled.

[Carl]

I am curious as to why he is no longer disabled? Perhaps he passed away in August? If so, then that does not change his status on your tax return and you *can* claim him as a dependent for the entire tax year.