SNAP & Medicaid caseworker here. Your mother should be entitled to a much higher monthly food stamp grant based on the information you provided. Based on the income and expenses you list (and assuming she pays a monthly Medicare Part B premium), she should be eligible for $157.00 per month in food stamps.

Have her call the PA DHS State Wide Customer Service Center at 877-395-8930. They can check to make sure her income and expenses are recorded correctly.