A person qualifying as your dependent:
generally may be your child, stepchild, adopted child, grand child, great-grand child, son or daughter in law, father or mother in law, brother or sister in law, parent, brother, sister, grand parent, step-parent, stepbrother or sister, half brother or sister, and, if related by blood, uncle, aunt, niece, or nephew. The above relatives do not have to live with you.
Also, any person, whether or not you are related to them, who is a member of your household for the entire tax year, except for temporary absences;
must receive less than $3,650 of gross income unless the dependent is your child and either under age 19 or a full-time student under age 24;
must receive more than one-half of his or her support from you;
cannot file a joint tax return with his or her spouse, unless the joint tax return is filed solely to obtain a tax refund when neither the child nor the spouse is required to file a tax return; and
must be a U.S. citizen or national, or a resident of the U.S., Canada, or Mexico.
It sounds like you should be able to claim the deduction. Neither of the parents can claim the deduction. You must also meet all of the requirements to claim a child as a dependent. You can refer to my legal guide entitled "Claiming your Child as a Deduction" to see the specific requirements. If you are still unsure of what you need to do you should see a local tax professional.
Any individual seeking legal advice for their own situation should retain their own legal counsel as this response provides information that is general in nature and not specific to any person's unique situation. Circular 230 Disclaimer - Advice given in this response cannot be used to eliminate penalties with the IRS or any other governmental agency.