A definitive published work on the DeRousse clan is Ruth Menard's book "A French Connection II". It contains almost 1600 members of the clan in 78 pages and tracks the family through 13 generations from 1675 to the mid-1990s.

The Henry DeRousse of interest was likely the Henry born in 1839 in Kaskaskia, IL. He was the son of Charles DeRousse, b. 1797 in Kaskaskia, and Modesto Chamberlain; they married on 30 May 1825 in Kaskaskia. Afraid I don't have any further information on where he is buried.