After many years of searching, I've found my great-grandmother's family. It appears that there may have only been one male descendant who might have carried on the family line.
Paul Dewey cApr1822 Belgium - Aft. 15 June 1900 probably Vermilion County + 1845/55 Gorling Marcelline (possibly Randall) c1830 Belgium - 1880-1900 possibly Illinois
1. Lewis-Louis cMar1856 Belgium - Aft. 15 June 1900. He married 1870/80 Melissa Unknown b.cDec1853 Masschusetts. She had a son, Irvin L. Whittamore, by a previous marriage. She'd had no other children before 1900.
2. Paul cMay1857 Belgium - 16 Sep 1918 Danville, Vermilion County. His wife is unknown, Paul was a widower by 1900. a. Charles Robert 3 Dec 1890 Danville - Aft. 5 June 1917 Unknown. + c1909 Eva B. Unknown c1894 Illinois. Children: Catherine M. and at least 2 other children.
3. Vitale-Vitole "Vital-Vitol" cFeb1858 Belgium - 22 Feb 1920 Catlin Twp., Vermilion County. + c1886 Mary L. Unknown cApr1866 Indiana. No living children by 1910.
4. Philip c1864 probably Illinois - Bef. 1880
5. Mary c1864 probably Illinois - Aft. 4 Aug 1870
6. Flora-Florine c1865 Illinois - Aft. 7 June 1880
7. Anna "Annie" 7 Jul 1866 South Danville - 5 Nov 1956 Wichita, Sedgwick Co., Kansas. + c1884 Charles Harry Hook 4 Apr 1863 Indiana - 1 Mar 1938 Wichita. Harry was a coal miner. Their children were; Mary Ann "Mamie" 1887 Kansas, Charles Harry, Jr. 1893 Kansas, Dollie L. 1896 Indian Territory, Florence 1897 Kansas, Arthur 1899 Kansas, Bert 1901 Kansas, Frank 1903 Kansas, and Alverta c1906 Kansas.
The Dewey's were coal miners. On the 1870 census the surname is recorded as DOEY, on the 1880 census it is recorded as DE TUY. Paul's name on his marriage record in Vermilion Co. is D'Tuy. The family spoke French and may account for the variances in spelling.