I'm not sure that his death cert will have his mother's maiden name. Different counties required different thing at different times. Also if no one from the family ever knew what her maiden name was then they could not report it to the county for the death cert.
You might want to try for his immigration paperwork.
Do you know who Ernest Ahlgrim's father was ??? Did he come to America ???
--- Other stuff I found.
Marriage Date: 15 Oct 1871 Marriage Place: , Saginaw, Michigan Groom's Name: Ernst Ahlgrim (Sr.) Bride's Name: Dorathea Numan --- Name: Ernest Ahlgrim (Jr.) Birth Date: 22 Oct 1876 Birthplace: East Saginaw, Saginaw, Michigan Father's Name: Ernest Ahlgrim (Sr.) Mother's Name: Dora --- 1880 Federal Census Records Michigan > Bay > Standish > District 27 > 3 Ernest Algrim 35 (b. about 1845)(GermanyGermanyGermany) Dorrett Algrim 35 (b. about 1845)(GermanyGermanyGermany) Lenna Algrim 11 (b. about 1869)(GermanyGermanyGermany) Charles Algrim 8 (b. about 1872)(MichiganGermanyGermany) Mary Algrim 6 (b. about 1874)(MichiganGermanyGermany) Ernest (Jr.) Algrim 4 (b. about 1876)(MichiganGermanyGermany) William Algrim 2 (b. about 1878)(MichiganGermanyGermany) --- 1890 Federal Census Records No Records Available --- 1900 Federal Census Records Michigan > Saginaw > Buena Vista > District 28 > 4 Ernest Argrim 55 (b. Sep 1844) Dora Argrim 54 (b. Sep 1845) Lena Argrim 29 (b. Nov 1870) Karl Argrim 27 (b. Dec 1872) Mary Argrim 25 (b. Oct 1874) Ernest (Jr.) Argrim 23 (b. Oct 1876) William Argrim 21 (b. Sep 1878) Albert Argrim 18 (b. Oct 1881) Record shows Ernest and Dora have been married for 30 years Record shows Dora has had 7 kids with 6 still living Record shows Lena has been married for 10 years, no kids Record shows Mary has been married for 5 years, no kids --- 1910 Federal Census Records Michigan > Saginaw > Buena Vista > District 32 > 17 Ernest Aklgline 65 Dora Aklgline 64 Record shows Ernest and Dora have been married for 40 years Record shows Dora has had 7 kids with 6 still living --- 1920 Federal census Records Michigan > Saginaw > Buena Vista > District 154 > 6 Ernest Algrim 75 Dorothy Algrim 75 John Miller 68 (half-brother) ---
Obit Index: SAGINAW NEWS COURIER Monday, May 05, 1924 (8) Name: AHLGRIM, ERNEST (Sr.) Spouse's Name: DOROTHY NIEMAN Married: 00/00/1870 Spouse's Death: 02/15/1923 Birth Date: 09/07/1844 Birth Place: GERMANY Death Date: 05/04/1924 Death Place: BAY CITY, MI Miscellaneous Year Moved to US/Saginaw: US/SAGINAW 1872 Cemetery: FOREST LAWN Funeral Home: DEISLER --- Obit Index: SAGINAW NEWS Monday, December 05, 1960 (B6) Name: AHLGRIM, ERNEST (Jr.) Spouse's Name: SOPHIA SYMONS Married: 00/00/1908 Spouse's Death: 00/00/1936 Age: 84 Birth Date: 10/22/1876 Birth Place: SAGINAW, MI Death Date: 12/05/1960 Death Place: SAGINAW, MI Miscellaneous Cemetery: BRADY HILL Funeral Home: CHILSON ---
I hope this information will be helpful to your research.