Ed, Are you sure you don't mean Washington Township in Marion County (which is the Broad Ripple area)? Because I was unable to find any trace of this Swan family in Hendricks County, but in the WPA marriage index for Marion County I did find:
--William Swan (born 1/1/1859) to Elizabeth Gentile (born 1887) 10/9/1913
I looked in the WPA index to births for Marion County and couldn't find any Swan/Swain entries that had William & Elizabeth as parents.
I would look at the 1900 census for William--he ay have had a previous marriage and children, based on his age.You could also look for him (or his son) on the 1920 Indiana Soundex, since you're not sure when he died.
For what it's worth, I looked on Heritage Quest's 1910 Indiana census index CD, and found these William Swans in the right age range:
--William Swan age 56 male white born Germany Marion County, Indianapolis, 13th Ward, Roll 369, part 2, page 196 --William Swan age 51 male white born England Grant County, Gas City, 1st Ward, Roll 351, part 3, page 18 --William E. Swan age 53 male white born Indiana Madison County, Anderson, 1st Ward, Roll 365, part 2, page 38