Some states provide a Medicaid benefit for assisted living facilities but many do not. Check with the facility. If it is available they will assist you. If it is available and she has assets of more than $15,000 seek help from an estate planning attorney in your area.
It depends on the type of facility and the other assets your mother has in her name. Medicaid will typically cover nursing home stays, but will not pay for assisted living. In addition, there is a financial resources test (both income and assets). You may want to contact an elder law attorney in your area to see if and when your mother may be eligible for additional benefits.