I think you may have combined a few different poeple into one. The William Westby listed in the 1910 census at the Norwegian Lutheran Children's Home in Chicago was 14 years old and born in Illinois. Your Roy William Westboy would have been 30 years old (if born in 1880). Also, the 1920 census shows a William Westby, born in Illinois ca. 1896 living in Dunkirk, Wisconsin. This is probably the one you found in the children's home in 1910.
Strange, that the Roy Westboy listed in the 1930 census shows his parents as being from South America.