Social Security benefits are only taxable based on other income being reported on the tax return.
Up to 85% of Social Security Retirement/Disability/Survivors benefits becomes taxable when all your other income plus 1/2 your social security reaches:
Married Filing Jointly - $32,000
Single or Head of Household - $25,000
Married Filing Separately - 0
If Social Security is the only income they receive then it does not matter how much is received as none of the SS benefits are included in the gross income.
However, if there is a large amount of SS benefits then they may be paying for over one-half of their own support. So in that case they could not be claimed as a dependent.
