Willoughby’s enthusiasm for a deathbed scene with Marianne is terribly creepy but I think in line with other sentiments about women and their usefulness to him. Women he uses for financial gain he has no scruples actually hoping for their death and women that he uses for pleasure he merely discards without a thought for their welfare or fate which is less reprehensible but still quite ugly sentiment.

Willoughby has been waiting for Mrs. Smith to pass and relieve his financial difficulties for years. His visits to her are obligatory (Ch. 44) to him—she receives little attention and he actively plans how he will transform her house with her money after her death while she sits ignored somewhere within. Poor aunt is clearly of no use to Willoughby except in death. Sophia’s saved Willoughby’s estate and him from a spunging house but now that he has her brass in pocket he hopes she will conveniently die and free him so he might turn his attention back to the still interesting Marianne.

Eliza stroked Willoughby’s vanity and satisfied his carnal pleasures temporarily. When she could no longer fulfill that role (due to her lack of understanding or pregnancy or both?) he abandoned her, “in a situation of the utmost distress, with no creditable home, no help, no friends, ignorant of his address” (Ch. 31) which could have led to a young death much like her mothers. Willoughby could not be unaware of the dangers to Eliza in such a situation so his abandonment if not actively malicious it is carelessly and unfeelingly negligent of Eliza’s (and child’s) welfare.

Willoughby said Marianne was the means for him “to pass my time pleasantly while I was obliged to remain in Devonshire” and when exposure of his affair with Eliza ended her usefulness he “left her miserable -- and left her, hoping never to see her again” (Ch. 44). His “regard” for her makes his abandonment and refusal to relieve her hope and anxiety in London with the truth that much worse. As Willoughby’s worry was of Marianne dying still thinking ill of him, as opposed to the fact she is dying; it is not surprising that he construes her death into another opportunity to service his vanity.