My mother in law passed away we received her income tax check two days after wards....?

She did not have any insurance so we really need this money to pay her final expense. Our bank will not deposit this check (even though they have deposited many of her other checks) we do not have power of attorney. She died suddenly and my husband is the oldest son and she had no husband. We have taken care of her estate and all the funeral expenses. Do not know what to do please help