I hadn't realized the connection before of George W. Hunt dying at age 46 in 1863 and four of his sister-in-law's children dying the same year.(George's wife was Catharine Schryder and her sister was Mary M. Schryder who married John Foster Buck.)I did find the following from "Portrait and Biographical Album of Otoe and Cass Counties, Nebraska" (Chicago: Chapman Brothers, 1889) on a portrait of John F. Buck at pages 935-937:
"He was married in Peoria County, Ill., Nov. 5, 1839, to Miss Mary Schryder, daughter of Ernest C. and Sarah Schryder. (For full parental history see sketch of her brother, George F. Schryder.) Mrs. Buck was born in Cayuga County, N. Y., near Lake Ontario, May 23, 1820, being next to the youngest of the family of three daughters and two sons born to her parents. When seventeen years of age she accompanied her parents to Peoria County, Ill., and remained an inmate of their home until her marriage with our subject. She received a good education in the schools of her native State, and a superior training in domestic duties from her excellent mother, which well fitted her for her position as companion, helpmate, counselor, and all that makes a true wife and faithful mother. To her and her husband there have been born ten children. The, names of the deceased are Charles D., James R., George N., Willie E. and Daniel W., all of whom died when quite young, and some of them of diphtheria."
Diphtheria was highly contagious so perhaps George Hunt also died of the disease, but it appears unlikely since George died in January and the first four Buck children all died in August (6th (James, age 8), 18th (Willie, age 1), 22nd (George, age 4) and 26th (Charles, age 11); Daniel died in 1865 at age 21 days).
You can read the full portrait of John F. Buck starting at page 935 at: