Claiming your elderly parents do not affect Social Security or Medicare. If she has another type of health insurance, such as a state insurance, then it may, but you would have to contact the state to find out.
To claim someone as a Qualifying Relative, they must be:
- Your child ( including step children, adoptive children and foster children) or a descendent of them
- Your sibling (including half siblings) or a child of your sibling or a sibling-in-law
- Your parent or grandparents, including step parents and in laws
- Any other person that lived with you for the entire tax year
- Not a qualifying child of another taxpayer
- Someone that you provided over half of their support for during the tax year
- Has less than $4,700 in income (not counting social security)
If she does meet the criteria to be a qualifying relative and you choose to claim her, then you would be able to claim the $500 Non-Refundable Other Dependent Credit as well as file as Head of Household.