Bror Gustaf was in Worcester for the World War I Draft Registrations
World War I Draft Registrations:
The Bror Gustaf I found was living in Worcester, Massachusetts, so unless yours was there for a while (but do you know? You have only found him in one census.), he isn't yours.
World War I Draft Registration Cards, 1917-1918
Name: Bror Gustaf Erikson
Birth Date: 13 Mar 1881
Source Citation: Registration Location: Worcester County, Massachusetts; Roll: 1674463; Draft Board: 1.
The image of the registration has more information than that. For example, he was a paper hanger. His nearest relative was Bertha Augusta Erickson. There is more, but the record is hard to read and I don't have unlimited time.