My mother was in a nursing home and on Medicaid and to my knowledge she had no assets. Now I have been informed that she had a life insurance policy, what should I do?

Two months after her death I was informed she had a life insurance policy. Not being aware there was a life insurance policy, I answered the letter from Medicaid Recoup Law that, to my knowledge, she had no assets. Now that I have been told of a life insurance policy that my sister was named beneficiary, what should I do? My sister had told me that the insurance policy had been given over to the funeral home as irrevocable.