Heart attack Click to see full answer. Then, what happened to Big Mama Thornton?Thornton was found dead at age 57 by medical personnel in a Los Angeles boarding house on July 25, 1984. She died of heart and liver disorders due to her longstanding alcohol abuse. She had lost 355 pounds (161 kg) in a short time as a result of illness, her weight dropping from 450 to 95 pounds (204–43 kg).Also, who did Elvis steal hound dog from? Big Mama Thornton Just so, when did Big Mama Thornton die? July 25, 1984 Who is Big Mama?Willie Mae “Big Mama” Thornton. Willie Mae “Big Mama” Thornton Willie Mae Thornton (1926-1984) was an influential African American blues singer and songwriter whose career extended from the 1940s to the early 1980s. She was called “Big Mama” for both her size and her robust, powerful voice.