Charles August Johnson

Where was Charles in the 1970 Federal Census? His older brother August (age 16) was listed at home with father John, mother Johanna, and infant sister Eda. Was Charles (age 15) living with some other family?
Death certificate?
Contact Oakwood? Are John/Johanna there too? Look on FaG. Any papers?

Historical Records

The 1877 book The History of Henry County, Illinois (p201) lists August, Charles, and John, but has enough other Johsons that it's difficult to know if these are matches.
The 1880 Census for Geneseo, IL includes John Johnson (age 62; laborer), Hannah (age 50; wife), Charles (age 34; laborer), Ida (age 10; daughter), and Emmanuel (age 6; son). Charles was born in Sweden. Ida and Emmanuel were born in Illinois.
Possible match for son Charles A Johnson's U.S. Naturalization Record on Oct 24, 1884
In the 1900 Census for Geneseo, IL, John G (age 81) and Johanna (age 70) are living at son Charles A's (age 45, single) home, along with younger son Emmanuel (age 25, single). John and Johanna have been married 48 years (since c. 1852). John G is still an alien, but Charles is a naturalized citizen. Johanna is listed has having had 6 children, but only 3 remain living. We know August was living, and this census shows Charles and Emmanuel were living, so Ida must have died, along with 2 other unknown children.
Charles August Johnsondied in Geneseo, Henry, Illinois on 26 Sep 1924. He is listed as a mason, born in Sweden. Parents are John Gustav Johnson (born in Sweden) and Johanna Anderson (born in Sweden). He is buried in Oakwood Cemetery (in Geneseo, IL).