Grandma Sawyer/3D Timeline

Grandma Sawyer is the deceased grandmother of the Sawyer family. She appears as a preserved corpse in The Texas Chain Saw Massacre and it is unknown when she died.

Biography
Grandma Sawyer died long before the first film starts. The Sawyers keep her corpse in the attic of their farmhouse and leave Grandpa Sawyer there to sit next to her throughout the day before dinner. It is most likely that her remains are burned in the fire in Texas Chainsaw 3D.

The Texas Chain Saw Massacre
She is first seen briefly during Leatherface's chase scene, Sally approaches her seeking help but finds her dead body in a chair next to Grandpa Sawyer, who she believes is also deceased. She runs away and is later captured by Drayton Sawyer.