This is how Humbert describes Lolita's mother, Charlotte Haze:
The poor lady was in her middle thirties, she had a shiny forehead, plucked eyebrows and quite simple but not unattractive features of a type that may be defined as a weak solution of Marlene Dietrich. (10.7)
Widow Charlotte is smart enough to impress people at a bridge gathering or a book club, but grossly inferior by Humbert's impossibly sophisticated standards of language usage. By Humbert's description, Charlotte is a real piece of work. To him, her taste in household décor more or less says it all:
The front hall was graced with door chimes, a white-eyed wooden thingamabob of commercial Mexican origin, and that banal darling of the arty middle class, van Gogh's "Arlesienne." (1.10.4)
Her dislike of her own daughter makes her even less likable to Humbert, who can only muster any passion toward her by reminding himself that she is related to Lolita. Her death by a car swerving to miss a dog is more tragicomic than anything. The sick part is the reader is relieved for Humbert.