August sunset

Watching a late August sunset with my sister. We sat on the front steps of our brother's house. He and his wife were out buying some chairs; their six children were in the house behind us playing with my three children. They made root beer floats. My sister called our mom to see how her heart ultrasound had gone. Mom said she gets to continue taking rat poison for two more weeks.
It was warm and quiet. I couldn't remember the last time I'd had such a peaceful moment around a relative. I was usually surrounded by loud and lively children. I asked my sister, "When do we start worrying?"
She shrugged and muttered, "I don't know."