I don't think anyone encased her. I think what they meant by mummification is that she was withered and dried in all that time of lying there dead on the floor.
I am always very saddened by deaths such as these. A number of years ago an elderly women was found dead in Worcester, MA after the tax assessor went to her house. She had been dead for 5 years. To be gone for 5 years and to have no one miss you?