If she falls into this criteria, you can claim her. Don't be tricked by the term relative, it can be an "unrelated" person also.
Under the qualifying relative rules:
- Not qualify as somebody else’s qualifying child or qualifying relative
- Live with you the entire year (365 days) or be one of these:
- Your child, stepchild, foster child, or a descendant of any of them
- Your brother, sister, half brother, half sister, stepbrother, or stepsister or a descendant of any of them
- Your father, mother, grandparent, or stepparent, but not a foster parent
- Your son-in-law, daughter-in-law, father-in-law, mother-in-law, brother-in-law, or sister-in-law
- Your uncle, aunt, nephew, or niece
- Earn less than $4,050
- Receive more than half of his or her support for the year from you
To claim a dependent, these must also be true:
- He or she can only have filed jointly with his or her spouse to claim a refund of the taxes withheld. Also, if he or she were to have filed separately from his or her spouse, neither would have owed taxes.
- The dependent is one of these:
- U.S. citizen
- U.S. resident alien
- U.S. national
- Resident of Canada or Mexico
You can’t qualify as a dependent on someone else’s return. This is true even if the other person doesn’t claim you on his or her return.