Hi, I'm not related, just finding what I can.
SSDI Martin L. Dommer 26 Apr 1894, (Norfolk, Madison Co, Ne)
d. Nov 1964 - Union Grove, Racine Co Wi.

1930 Wi, Winnebago Co, Oshkosh
Martin L. Dommer, 35, 1st mar @ 21 b. Norfolk Neb. (this is unusual to name the town) parents b. Neb, teacher
Anna 45, 1st mar @ 29, b. Maple Grove Wi., parents b.Ger
Ruth L, 8, b. Oshkosh
Virginia 6, b. Oshkosh
Robert 5 b. Oshkosh

Not sure where Martin was 1920

WWI draft reg - Menominee Co, Mich Martin L. Dommer b. 26 Apr 1894, Norfolk, Neb , married, teacher

Martins parents were Ludwig and Sarah
Ludwig b. 1871 Michigan
Sarah b.1873 Nebraska
Martins siblings (he was oldest)
Norah b.1896
Reuben 1899
Esther abt 1903
Leona abt 1913

Ludwigs parents were William b. 1830 Prussia d.1912 Ne.
and rosina (poss. Muller)b. abt 1836 prus, d.1894 Ne

The census has Dommer spelled many different ways.. mostly transcription errors.

Looks like William and Rosina had a large family
about 1865 to Canada, then about 1869 to Michigan, about 1872 to Norfolk Neb.
2 children b. Prussia
1 b. Canada
3 b. Mich
2 (maybe more) b. Neb.

1870 census Mi, Iosco Co, Grant
indexed as Dunner. has a Anna age 75, living with them Williams mother?

also, next door, there is a Herman Dunner family 5 children,
2 b. Prus
2 b. Can
baby b. Mi.

There is an old query on Madison Co Neb. site
Marvin Dommer g-grandson of Rudolf, Ludwigs brother
sfsmfd@webtv.net (this is very old, may not work)

Good luck
Judy