Open Question: Can someone be claimed as a dependent even do person is a caregiver being pay less than $3,000.00 a year?

My mom is helping me with my 3 boys (1 is disable) but my brother file his taxes putting her down as a dependent because she is not working. I was ask by the person doing my taxes if I wanted top put her down as a caregiver because she helping me out but she only made less than $3,000.00 so she ain't doing taxes can I still put her down as a caregiver or not?? IRS ask for her SS# so not sure if my brother won't get in trouble for putting her down as a dependent and me as a helper What's the min you need to make in order to File a Federal Income Tax Return in 2009?