We know William is the brother Jesse Chisholm based on the surviving estate papers in Arkansas for a man name Corn Tassel, who was their maternal uncle. Corn Tassel is not the famous Cherokee Chief by that name, but a man who appears to be a member of the Old Settlers who came from the homeland in the East to Arkansas. His wife and children had all predeceased him leaving this sister's children as his only heirs. William is found in these records dated from 1841. "A" William Chisholm is also found on the Old Settler Payment Roll in 1851. We think that this entry is for Jesse's brother as by the 1896 final payment roll for the Old Settlers, he is listed as deceased with Jesse' children as his heirs indicated he had no surviving children. There are several researcher claiming that William is the same man found in Pennsylvania, born Feb 1821 and died 18 Feb 1895 in Fulton County, Pennsylvania and buried at Cedar Gove Cemetery in Dott. This man is found in census for Pennsylvania as the son of a Scotsman and secondary sources say his father is John Chisholm who came from Scotland to Bucks County, Pennsylvania.
https://www.wikitree.com/wiki/Chisholm-830
