1. You do not need to claim her SSA income.
2. You cannot claim your disabled girlfriend for EIC because she must be "your child." See the definition below.
To count as a qualifying child for EIC, your child must have a valid Social Security number (not an ITIN).
S/he must also:
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Be your child (including legally adopted), stepchild, eligible foster child, sibling, half-sibling, step-sibling, or a descendant of any of them (for example, your grandchild or niece); and
- Be permanently and totally disabled OR under the age of 19 as of December 31, 2017 (under 24 if a full-time student) and younger than you (or your spouse, if filing jointly); and
- Have lived with you (or your spouse, if filing jointly) for more than half the year; and
- Not file jointly with their spouse unless they weren't required to file.
3. You could possibly claim her as a regualr dependent (not EIC) if she meets these qualifications:
A person can still be an other dependent (Qualifying relative in IRS parlance, even though they do not have to actually be related), if not a Qualifying Child, if he meets the 6 tests for claiming a dependent:
1. Closely Related OR live with you ALL year
2. His/her gross taxable income for the year must be less than $4,000 (2015). Social security doesn't count as income
3. You must have provided more than 1/2 her support
4. She must be a US citizen or resident of the US, Canada or Mexico
5. She must not file a joint return with his spouse or be claiming a dependent of his own
6. She must not be the qualifying child of another taxpayer
Social security doesn't count as income, for the income test, but social security money he/she spends on her self does count as support not provided by you, for the support test. Money she puts into savings & investment does not count as support she spent on herself. If no one person provides 50% of the support (for example her relatives are also sending support), then a "multiple support agreement” (IRS Form 2120) can be used, to allow you to claim the dependent.
