Is there any tax break we're eligible for?

My 82 year old mom lives w/us for 12yrs - we haven't claimed her due to her income being +3,950. She is our dependent for all intent and purposes - she pays no rent or expenses, and although she is not disabled, we are her caregivers, living on extremely modest income.- we have seen her through two bouts of cancer in the last 3 years. I cannot believe there is NO type of tax break due to a few minimal dividend checks she receives throughout the year - please help, we are desperately trying to make ends meet as is!