Your question may be academic. There is a credit for the elderly or disabled (you don't have to be both). But because it has not been adjusted for inflation since 1983, very very few people qualify. If you qualify, TurboTax (TT) will automatically calculate it. It goes on Schedule 3, line 6 (2019). Box c should be checked and “Sch R” placed on the line next to that box. It is not a refundable credit. That is, you must have a tax liability to offset to get the credit. Very few people, with that little income have an actual tax to offset.
Having any social security income at all works against you. Essentially your potential credit is reduced by any tax you "shoulda paid” on the untaxed Social security income. If you have more than $5000 social security ($7500 Married Filing Jointly and both are elderly or disabled) or VA benefits you will not qualify for the credit.
That said, no specific medical diagnosis (including Cirrhosis of the liver) constitutes disabled to tax purposes.
“The term ‘disability’ means, with respect to an individual –
(a) a physical or mental impairment that substantially limits one or more of the major life activities of such individual;
(b) a record of such impairment; or
(c) being regarded as having such an impairment.”
For the IRS, disabled means -
"an individual shall be considered to be disabled if he is unable to engage in any substantial gainful activity by reason of any medically determinable physical or mental impairment which can be expected to result in death or to be of long-continued and indefinite duration. An individual shall not be considered to be disabled unless he furnishes proof of the existence thereof in such form and manner as the Secretary may require. "
I believe the substance of that paragraph is that it is your Doctor's decision
- He or she cannot engage in any substantial gainful activity because of a physical or mental condition and
- A doctor determines the condition has lasted or can be expected to last continuously for at least a year or can lead to death.
