There are several government programs, in addition to her company pension, that might provide help for your sister. She can apply for Social Security retirement or disability benefits based on Social Security Administration's web site.
her years of work, or on the work record of her spouse if she was married. She can apply for benefits online, with your help, at the
For help with medical costs, she should apply for Medicare coverage if she hasn't already done so. Medicare Part B covers some home care, which could provide you with important help with your sister. If she's not 65 years old yet, she'll become eligible for Medicare after two years of qualifying for Social Security Administration disability benefits, or when she turns 65, whichever comes first.
If your sister has few savings or other assets -- not counting her house as long as she still lives there -- she may be eligible for Supplemental Security Income (SSI) in addition to Social Security benefits. Low income and assets might also make her eligible for Medicaid, which pays most of the costs of medical care that Medicare does not pay. Contact your county's local social services office to apply for both SSI and Medicaid.