SSI and inheritances. Does she need a special trust fund?

My Mother and Grandmother live together. My Mother is her unofficial caretaker. My Grandmother is going to leave her $50,000 in her will when she passes. My Grandmother is 87 with health conditions and chronic pain. My Mother is on SSI, Diababilty, EBT, Mass Health. When my Grandfather passes years ago he left her $10,000. The inheritance he left her is still effecting the amount she recives from SSI to this date. My Mother and Grandmother would like to know what they could do so her assistance would not be affected. Thank you.