It's possible that he was the same person as:

United States Census, 1860

Name: Frank Raker

Residence: , Cook, Illinois

Ward: Township Of Leyden

Age: 18 years

Estimated Birth Year: 1842

Birthplace: Darmstadt

Gender: Male

Page: 185

Family Number: 1249

Film Number: 803169

DGS Number: 4213435

Image Number: 00190

NARA Number: M653

United States Census, 1880

Name: Charles F. Raker

Residence: Vincennes, Knox, Indiana

Birthdate: 1842

Birthplace: Germany

Relationship to Head: Self

Father's Birthplace: Germany

Mother's Birthplace: Germany

Race or Color (Expanded): White

Ethnicity (Standardized): American

Gender: Male

Martial Status: Widowed

Age (Expanded): 38 years

Occupation: Grocer

NARA Film Number: T9-0289

Page: 476

Page Character: A

Entry Number: 1410

Film number: 1254289