Hester, the mother, is a character who feels defeated by life. "She married for love, and the love turned to dust." Outwardly, she appears to care for her children, but in her heart she does not love them. She is troubled by something she does not quite understand. As a result of these feelings, she is cold and self-involved.
Hester blames their lack of money on bad luck. She tells Paul that luck is what brings in money. Being born into a situation or economic system with disadvantages is unlucky. But Hester and her husband probably are not faced with these kinds of dire limitations. So, blaming their lack of fortune solely on poor luck is disingenuous. In other words, she should work harder and be more responsible with money in order to change their financial situation. When Paul arranges to have his mother receive 1,000 pounds a month from their lawyer, she asks for the entire 5,000 pounds. She spends money on luxuries rather than saving it for necessary things like food, clothing, etc.
Although the mother does outwardly care for her children, she does not truly love them. She is irresponsible with money and blames her misfortune on bad luck. And even though she doesn't know that Paul is the one bringing in the money, she does rely on this source of income rather than trying to do the work herself. In these respects, she is selfish and wasteful.