Q. Because she was not ACTUALLY taxed on it because she had no other income and she owes no tax, I can claim her as a dependent?
A. That is correct. Another way to look at it is: although the whole $11,000 SSDI goes on line 6a of her form 1040, it's the $0 amount on line 6b that counts for the income test. https://www.irs.gov/pub/irs-pdf/f1040.pdf
Nontaxable Social security doesn't count as income, for the income test, but social security money she spends on her self does count as support not provided by you, for the support test.
