In the story, negi's father intervenes so that she does not have to her mother in the kitchen. what can you infer from this?

Negi's father is the leader of the family.

The most likely situation is that Negi's father is the leader of the family. This is likely because of his actions. If Negi's father is able to intervene in a way that means she does not have to help her mother, then it is likely that Negi's father is the leader of the family, and that the other members tend to do whatever he believes is right.