Sybil is an unlikable character so the entire novel rings false to me.
Perhaps we’re meant to have sympathy for her as she lost a child years before, or perhaps because she is going blind, but I cannot conceive why people are fond of her or why men seek her out romantically in her 70’s. She is closed, hard, petty, and selfish yet spills warm needlessly long prose when writing to people she doesn’t know.
A note to the author: As someone slightly younger than this character I find Sybil speaks like someone a generation older than me.