Who can claim a parent as an dependent?

Which sibling can claim a parent as an dependent?

In recent years, my brothers and I have had to pool resources to help our dad, who has little annual income besides Social Security. This year, our combined payments will total more than half his support. Can we claim him as a dependent?

One of you may be able to if that person has paid for at least 10 percent of your father's support, none of you has paid more than half, and your father's gross income doesn't top $3,500 in 2008. You can decide among yourselves who'll get the dependency exemption. That sibling must file Form 2120, "Multiple Support Declaration," with his 2008 tax return. He also must get signed statements from the others waiving their right to claim the exemption for that year. Each year a different sibling can claim the exemption, if you want to take turns.