In chapter 13 how does Aunt Alexandra treat Calpurnia, their maid? What does this tell you?

Chapter 13
"Put my bag in front bedroom, Calpurnia," was the first thing Aunt Alexandra said. "Jean Louise, stop scratching your head," was the second thing she said.
Calpurnia picked up Aunty's heavy suitcase and opened the door. "I'll take it," said Jem, and took it. I heard the suitcase hit the bedroom floor with a thump. The sound had a dull permanence about it.
"Have you come for a visit, Aunty?" I asked. Aunt Alexandra's visits from the Landing were rare, and she traveled in state. She owned a bright green square Buick and a black chauffeur, both kept in an unhealthy state of tideniess, but today they were nowhere to be seen.
"Didn't your father tell you?" she asked.
Jem and I shook our heads.
"Probably he forgot. He's not in yet, is he?"
"Nome, he doesn't usually get back till late afternoon," said Jem.
"Well your father and I decided it was time I came to stay with you for a while."
"For a while" in Maycomb meant anything from three days to three years. Jem and I exchanged glances.