If your son is permanently and totally disabled you can claim him as a dependent if he lived with you for more than half the year, did not provide more than half of his own support for the year, and did not file a joint tax return with a spouse. His income doesn't matter, and it doesn't matter whether you provided more than half of his support, as long as he did not provide more than half of his own support. Under these circumstances he is a qualifying child, not a qualifying relative, and he is also a qualifying child for the Earned Income Credit. Whether you actually get the Earned Income Credit depends on your income and other factors besides your son being a qualifying child.
