Yes, most likely. Social security does not count as income for the dependent income test (#2 below), but there are other dependent tests to meet.
There are two types of dependents, "Qualifying Children"(QC) and
standard ("Qualifying Relative" in IRS parlance even though they
don't have to actually be related). There is no income limit for a QC but there
is an age limit, a relationship test and a residence
test. Only a QC qualifies a taxpayer for the Earned
Income Credit and the Child Tax Credit.
A person can still be a Qualifying
relative dependent, if not a Qualifying Child, if he meets the 6 tests for
claiming a dependent:
1. Closely Related (a parent is) OR live
with the taxpayer ALL year
2. His/her gross taxable income for the year must be less than $4,050 (2017), $4150 for 2018.
3. The taxpayer must have
provided more than 1/2 his support
In either case:
4. He must be a US citizen or resident of the US, Canada
or Mexico
5. He must not file a joint
return with his spouse or be claiming a dependent of his own
6. He 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. Note that a parent is closely related so there is no requirement that
she live with you at any time, during the year. But if you provided a home it
helps your support case, unless they own the home you live in. If no one person
(or married couple) provides 50% of the support (for example your siblings are
also sending support), then a "multiple support agreement” (IRS Form 2120)
can be used, to allow you to claim the dependent. https://www.irs.gov/pub/irs-pdf/f2120.pdf
The IRS has a worksheet that
can be used to help with the support calculation. See: http://apps.irs.gov/app/vita/content/globalmedia/teacher/worksheet_for_determining_support_4012.pdf The support
value of a home is the fair market rental value, divided by the number of
occupants.
