Nation 10-year-old boy dies saving his sister from drowning in South Dakota river June 14, 2021June 14, 2021 Alfonzo Galvan, Sioux Falls Argus Leader Comments Off on 10-year-old boy dies saving his sister from drowning in South Dakota river Multiple agencies assisted the LCSO in searching the Big Sioux River for a missing 10-year-old boy, a post on Facebook stated.