Consider the following:
Beli and Lola are very similar in terms of personality. How does this cause difficulties between the two women? How is Oscar different from his mother? How do these differences make their relationship easier?
Beli does seem to have different expectations and standards for Oscar because of his gender. How does Oscar's gender affect his mother's expectations for him/treatment of him?
Beli wants to make sure that her children do not suffer the same pain she does. For most of the story, it seems like Lola is more at risk, so Beli comes down harder on her. Can you think of a time where Oscar is suddenly at risk and Beli's treatment of him changes/becomes harsher?