The real Charles Frederick Ingalls died at the age of 10 months. There are no records indicating what he died of.
Charles Frederick Ingalls, Jr. (November 1, 1875 - August 27, 1876) was the only one of the Ingalls' children born in Walnut Grove, Minnesota.
Although the church bell was put up two episodes prior, it was missing from the church in both episodes of this two-part show, meaning the episodes were aired out of sequence.
The Wabasha County (Minnesota) death records (Book A, page 135) show that "Fred Ingles" [sic] died August 27, 1876; the cause of death was listed as diaorrhora (an often-used spelling for diarrhea in these death records). A number of other children in the county from ages 28 days to a year old died of the same cause that year. Diarrhea can quickly cause dehydration in children and can lead to death in only a few days.