If a woman was put into a nursing home and her SS checks were deposited into her account for the first 3 months, can we use the money for her burial?

I assume that Medicaid paid for the woman's nursing home care?  If so, there are strict rules about what happens to her money.  Anyone who fails to follow these rules could be charged with a criminal offense and certainly could be required to return the money.  The penalties are serious enough that you should contact your state's Medicaid authorities to ask this question.