Complex sentence: Gladys is Billy's mother and Harold's wife is a loving, tolerant, and patient, yet mentally unstable woman brought on by having to deal with her family, and Grim as an eternal guest.
Split into simpler sentences: Gladys is Billy's mother and Harold's wife. She is a loving, tolerant, and patient, yet mentally unstable woman brought on by having to deal with her family, and Grim as an eternal guest.