There are several kinds of assistance available for your mother. Because of her age and low assets, she's almost surely eligible for Supplemental Security Income (SSI), in addition to whatever Medicaid, which can pay almost all her medical bills that aren't paid by Medicare. Medicaid can also cover home care visits to your mother when she needs occasional help. She can apply for both SSI and Medicaid at her local county social welfare or social services office. One application can serve for both programs.
Social Security benefits she receives. This could bring her an extra $600 to $800 per month. If she qualifies for SSI, she'd also qualify for
Medicaid eligibility also means that she can join a Medicare Part D prescription drug insurance plan for little or no monthly premium, and with the plan and she'll pay only a very small co-payment for prescription drugs.