Megosztott hang

AITA for telling my sister to correct her child? My sister's youngest daughter (5) told me she would like for me to be dead so she wouldn't have to deal with "an annoying aunt" anymore. For background, I had done nothing to her that day, in fact we were driving home from a very fun day spent with family where I had taken her swimming. Regardless, I know that kids don't always understand what death means but, should be corrected if they wish it on others. (right?) My sister was in the car with