Will try and help.
1st thing, the Harry you saw in social seurity death index was born 17 jan 1912 not 1922
Violet NELSEN,age 18 of NORTHFIELD,married Gustav HERTEL of Mt. Prospect in West Northfield(township)Cook by minister G.W.MAEDE post office box WHEELING,Cook,IL
1900 census NORTHFIELD township Cook,IL
NELSON
Thomas Oct 1845 Scotland,USA 1868,married 1869
Minnie,Oct 1851 Scotland,USA 1868,married 1869,had 14 children-11 alive now
William Jun 1873IL
VIOLET Aug 1883IL(year is wrong should be 1885)IL
Nathaniel Nov 1885 IL(Nathan died 5 May 1965 obit sis Violet Westfall)
Edward Jan 1889 IL(Edward Dixon obit 15 aug 1955 sister Violet WESTFALL)
George Jan 1891 IL(obit George L. 3 may 1961 sister Violet WESTFALL)
Jessie Nov 1892 IL
Grace Sep 1894 IL
Harrey Jul 1896 IL
(NOTE Violet Forsythe Nelson's birth name..usual for scots to use a surname of ancestor for a middle name..in this case Forsythe)
Gustav is in Elk Grove township,Cook,IL b. Jun 1879 Germany,USA 1894 under his parents Louis wife Augute(Augusta?)
next time I found them
1920 census Chicago 29th ward,Cook,IL
HERTEL
GEORGE A(Gustav Adolf on birth cert=George A. here)1881 Germany
VIOLA(aka Violet)1885
Williamina 1908 IL(matches birth cert 1907)
Alma,1911,IL
Harrie 1913 COLORADO age 7
Elinore 1916 IL
Margarete 117,IL(birth cert Margaret Bertha 1916)
John 1919,IL(birthy cert Howard John 1918)
IL State Archives death index 1916-1950
Cook County
Chicago
HERTEL
Gustav A., died 31 Oct 1945
Lake County
Waukegan
HERTEL
George A.,died 20 Apr 1944
(WHEN & WHERE did Robert L. WESTFALL marry Violet? might help determine some more info)
Now WESTFALLs
Robert L. b. 23 Dec 1892 died Jan 1976 Arvada,Jefferson,CO
wife Violet b. 25 aug 1885 died Mar 1980 same location
(violet's matches census 1920 The 1900 census yr is off by 2 but month matches)
1900 census Victoria village,Copley township,Knox Co.,IL
WESTFALL
John A. Aug 1852 OH,father VA mother OH
LEONORAH,Nov 1856 IN parents OH,married 1872,had 11 children-11 alive now
Etta H.,Jul 1883,KANSAS(parents in Marion,Burbon,KS in 1880 census)
Eugene H.,Jun 1885 Il
Katie L.,Aug 1887 IL
Minnie F.,Oct 1889 IL
Unice P.,Oct 1891 IL
John A.,Sep 1893,IL
ROBERT L.,DEC 1895 IL(3 years off should be 1892 but month is right)
1910 census they're in Oneida 1st ward,knox co.,il
1920
Weld,CO
IL State Marriage Index to 1900
WESTFALL John to Leonora WOLF 30 Jul 1874 Knox County
cert # 00003287
contact Mollie Kennedy for copy
mollx.com
1860 and 1870 census WESTFALL
John found with parents Copley township,knox co.,IL
suggestions in case you havge gotten
1. get obits on Robert wife Violet,son Robert N...try library in city where they died also check Galesburg,Knox Co.,IL
2.check through your local library for access to databases such as
newsbank america's genealogy bank and hertitage quest.
3. post to Cook County board for Nelson and Hertel
4. Post to Knox Co.,IL for WESTFALL and WOLF
5. Check with Galesburg,Knox Co.,IL library for obits on
WESTFALL-John and lenora,etc.
6. check for genealogy/historical societies knox county,il
Hope these help
Kathy