How did inciang become a big sister to itong?

In the story, Inciang becomes a big sister to Itong when she takes on the responsibility of caring for him after their mother passes away. Despite her young age, Inciang embodies maturity and love, guiding Itong through life's challenges. Their bond strengthens as they navigate hardships together, with Inciang's nurturing nature helping Itong feel safe and supported. This relationship highlights themes of familial love and resilience in the face of adversity.