Julius F. Cornelius appears on the 1910 census for King County, Washington (Seattle), living with his family:
FATHER- Walford Cornelius,60 years old, a widower, born in Sweden, immigrated in 1882, and worked for the city of Seattle.
BROTHERS- Charles W. Cornelius, 28, a logger
George, 25, a blacksmith
Oscar, 23, a meat cutter,
Julius, age 21, listed himself as a sailor
The sister, Hilda, was 17 and had no occupation. The oldest son, Charles, had been born in Sweden and also immigrated in 1882. The other three sons were born in Minnesota, and Hilda was born in Washington, so they must have moved west around 1893.
Charles Walfred and George Cornelius also registered for the draft, so you can see their exact birthdates that way. There is a listing for a George Cornelius in the WA death database.
On the 1920 census, Walfred (69) and his son George still live in Seattle. Next to them lives the oldest son, Charles, and he was married to Alice. They had a daughter, Hope, age 16, but I cannot see any listing for Julius after 1910. Maybe someone else can find him.