What happened to the children’s mother? Explain Calpurnia’s function in the Finch household.

In Ch.1 we find out that that their mother died of a sudden heart attack. She was 15 years younger than Atticus, which made it very unexpected. Scout was only two when her mother died so her memories are vague at best and her trauma was minimal. Jem was six and he remembers more. Scout can tell that he misses their mother. Although Calpurnia is there to help with the house chores, she becomes a mother-figure to both Scout and Jem.