As the awkward conversation about Mrs. McPherson’s future drags on, Adelaide's remarks about caring for her mother are full of situational irony and hyperbole:
It’s work and care, Ellen, and you may as well admit it. You need all your strength—with those sickly children and Edward on your hands. When she comes to me, there need be no expense, James, except for clothes. I have room enough and Mr. Oswald will never notice the difference in the house bills—but he does hate to pay out money for clothes.
Adelaide speaks as though she is trying to convince Ellen not to take in their mother by listing all the challenges it would bring. This is situational irony: she's doing this not because she's worried about Ellen but because she doesn't want to take care of Mrs. McPherson herself. She pretends to be concerned that Ellen already has too much to handle with her “sickly children and Edward” to look after. However, it is really Adelaide who doesn’t want the extra responsibility.
Adelaide also uses hyperbole when she talks about the "work and care" involved in looking after their mother. She makes it sound like taking her in is going to be a huge burden for her, but deflects responsibility for this selfishness by making it sound like she wants to take it on. She also says that "Mr. Oswald will never notice the difference in the house bills," which in any other circumstances might seem like an argument for taking Mrs. McPherson into her home. However, at the same time, she complains about her husband not wanting to spend "money for clothes" when James has the financial freedom to spend whatever he wants. By saying this, she makes it look like she and her family would struggle financially if they took the widow in, hoping this will convince her brother that it’s his job.
When her son and daughters express concern about how she plans to live, Mrs. McPherson uses hyperbole to explain that she has enough money to do whatever she wants:
One thousand I have put in the savings bank—to bring me back from anywhere on earth, and to put me in an old lady’s home if it is necessary. Here is an agreement with a cremation company. They’ll import me, if necessary, and have me duly—expurgated—or they don’t get the money. But I’ve got five thousand dollars to play with, and I’m going to play.
Mrs. McPherson jokingly reassures her children that she has a thousand dollars saved that could bring her back "from anywhere on earth." This money, which she intends to use to be—finally—independent could even pay for a stay in an elderly persons' home if she needs it. She talks about having an agreement with a cremation company in a funny way, suggesting that if they don’t send her back as ashes they won’t get paid. As her exaggerated language makes clear, all of the duties that her children would traditionally take on have been taken care of. She is solely responsible for herself.
This comment about the money being able to “bring her back” from anywhere shows how joyful and free she feels now that her husband is gone. It's an over-the-top way to say she has the means to do whatever she wants, and that she intends to "play" with it all. Her casual mention of cremation and the playful word "expurgated" show that she also feels free to joke about serious things like death, even after her husband’s funeral.