History is what it is. I had a great grandfather who disappeared from his farm and home in Klemme, Iowa, in about 1905. He took a load of cattle to Chicago by train, and was never seen again. He left a wife and six children in Iowa. Decades later it was learned that he died in Chicago during the 1930's. If Isaac G. Evans did what he appears to have done, he was a flawed human just like all of us.
I checked the 1850 and 1860 census for Isaac, and found this:
The 1850 census for Natchez, Adams County, Mississippi, lists Stephen O'dell, gunsmith, age 29, born in New York.
The next entry (and household) was Joseph Evans, gunsmith, age 43, born in Ireland. The rest of Evans' household included-
Mary Evans, age 30, born in Ireland; Phebe Evans, age 12, born in Pennsylvania; Maria Evans, age 10, born in Virginia; Wm. Evans, age 7, born in Virginia; and Isaac Evans, gunsmith, age 27, born in Ireland.
The 1860 census lists, in Clayton Township, Crawford County, Wisconsin, PO Bell Center.
Isaac Evans, gunsmith, age 39, born in Ireland; Jane Evans, age 37, born in England; George Evans, age 11, born in Illinois; Joseph Evans, gunsmith, age 41, born in Ireland; and William Evans, a farm hand, age 17, born in Illinois.
The ages of both Evans brothers differ in every listing. Clearly, Joseph was older, but how much older varies from two to almost twenty years, in different sources.