Why is Scout being morbid with Miss Maudie?

Scout is conversing with Miss Maudie about Boo and wants to know if he's still alive..... her talk of death leads Miss Maudie to say Scout is being morbid.

“Miss Maudie,” I said one evening, “do you think Boo Radley’s still alive?”
“His name’s Arthur and he’s alive,” she said. She was rocking slowly in her big
oak chair. “Do you smell my mimosa? It’s like angels’ breath this evening.”
“Yessum. How do you know?”
“Know what, child?”
“That B—Mr. Arthur’s still alive?”
“What a morbid question. But I suppose it’s a morbid subject. I know he’s alive,
Jean Louise, because I haven’t seen him carried out yet.”