This is because while Elly does think that she is old, old, old and her life is all used up and John will leave her for someone younger, she assumes that her decrepit state is somehow indefinite despite her assuming the young person's assumption that if her husband were to actually die, her duty would be to waste away and perish of grief so as to join him in oblivion instead of living for her children. This is why most of her concerns as to his absence from her life involve pretty faces who want to laugh at her misery, not well-wishers who are sorry for her loss.
Hmmmm. How very odd. I've just realized that she doesn't really think that old women should be alive because they're just taking up space because they should be with their dead husbands. Widowers are okay because they can marry and reproduce but old ladies just eat without producing young so must perish.