A qualifying relative is similar to a qualifying child in that it must meet several tests. Generally speaking, the Qualifying relative is a dependent adult as opposed to a qualifying child and must meet similar tests. They are as follows:
Gross Income – The dependent earns less than the exemption amount for the tax year (For example, $3650 for tax year 2010),
Total Support –You provide more than half of the dependent's total support during the year,
Relationship – They must be related as a son or daughter, grandson or granddaughter, stepson or stepdaughter, or adopted child, brother or sister, half- brother or half-sister, step-brother or step-sister, mother or father, grandparent, stepmother or stepfather, nephew or niece, aunt or uncle, son-in-law, daughter-in- law, brother-in-law, sister-in-law, father-in-law, or mother-in-law, or foster child by court order or by a government agency. Relationship does not change due to separation or divorce (for example, mother-in-law). If the dependent does not meet the relationship test, the dependent must have lived with you all of the tax year.
Joint Return– If the dependent is married, he/she cannot file a joint return with his/her spouse.