The date of death on tombstone is incorrect. Per the records of Gratiot county he died on March 31,1868.
Civil War Veteran - CO F 13th Mich Infantry

Son of Elijah and Frelove Bigelow.

Message From find a Grave Contributor on December 23, 2020
My information is that Abel never married. The written bio information indicates he was married to Eliza. I believe Eliza was married to Zadock Bigelow. Also there in information toward the bottome that in 1960 he lived in west Michigan with his spouse (Eliza) and child) I believe this is a different Abel

U.S. Civil War Record
Name: Abel Bigelow
Enlistment Age: 21
Birth Date: abt 1840
Enlistment Date: 23 Dec 1861
Enlistment Place: North Shade, Michigan
Enlistment Rank: Private
Muster Date: 17 Jan 1862
Muster Place: Michigan
Muster Company: F
Muster Regiment: 13th Infantry
Muster Regiment Type: Infantry
Muster Information: Enlisted
Muster Out Date: 16 Jul 1862
Muster Out Place: Louisville, Kentucky
Muster Out Information: disch
Side of War: Union
Survived War?: Yes
Residence Place: Gratiot County, Michigan
Title: Record of Service of Michigan Volunteers 1861-65

Michigan, Deaths and Burials Index, 1867-1995
about Able Bigelow
Name: Able Bigelow
Birth Date: abt 1837
Birth Place: New York
Death Date: 31 Mar 1868
Death Place: Pine River, Gratiot, Michigan
Death Age: 31
Occupation: Farmer
Marital Status: Single
Gender: Male
Father Name: Elijah Bigelow
Father Birth Place: Pine River
Mother Name: Emalin Bigelow
Mother Birth Place: Pine River
FHL Film Number: 985691

Note: Death date on headstone, Mar 38, 1869

Headstones Provided for Deceased Union Civil War Veterans, 1879-1903
about Abel Bigelow
Name: Abel Bigelow
State of Cemetery: Michigan
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1850 United States Federal Census
Name: Abel Biglow
Age: 12
Birth Year: abt 1838
Birthplace: New York
Home in 1850: Howell, Livingston, Michigan, USA
Gender: Male
Family Number: 267
Household Members:
Name Age
Elijah Biglow 55
Frelove Biglow 40
Matilda Biglow 19
Ebeneazer Biglow 16
Abel Biglow 12
Abraham Biglow 9
Mary Biglow 8
Phebe Biglow 6
Zedach Biglow 4
Francis Biglow 1