Yes, it is entirely normal for an elder sister to be closest to her younger brother in a family. The dynamics and relationships within families can vary widely, and there is no one-size-fits-all rule for how siblings interact with each other.
Sibling relationships are complex and can be influenced by factors such as age, personality, shared interests, upbringing, and the overall family dynamic. It's not uncommon for siblings who are closer in age or have shared experiences to form strong bonds with each other. In some cases, an elder sister may take on a nurturing or protective role towards her younger brother, leading to a close and special connection.
It's important to remember that every family is unique, and the strength of sibling bonds can differ from one family to another. What matters most is the quality of the relationship and the mutual love, respect, and support shared between siblings. Whether an elder sister is closest to her younger brother, or if other family members have different dynamics, what truly counts is the care and understanding that family members have for one another.