I've been asked a couple of times about the applicability of the IRS Exemptions for Dependents. If you support your parents or siblings during their extended stays, you might be able to exempt up to $3,900 per person if you and your qualifying relatives meet the IRS "Rules for Claiming an Exemption for a Dependent". You may find your answers at the IRS Publication 501 at http://www.irs.gov/publications/p501/index.html
. You may also find helpful the IRS questionnaire available at http://www.irs.gov/uac/Who-Can-I-Claim-as-a-Dependent%3F
. In short, the insert from the IRS Publication 501: "(1) You cannot claim any dependents if you, or your spouse (if filing jointly), could be claimed as a dependent by another taxpayer; (2) You cannot claim a married person who files a joint return as a dependent unless that joint return is filed only to claim a refund of withheld income tax or estimated tax paid; (3) You cannot claim a person as a dependent unless that person is a U.S. citizen, U.S. resident alien, U.S. national, or a resident of Canada or Mexico; (4) You cannot claim a person as a dependent unless that person is your qualifying child
or qualifying relative."
To read more about the applicable test rules, follow this link Exemptions for Dependents