He was sometimes called by the nickname “Mormon John”.

I cannot find him in the Kentucky death records, even searching very broadly.

The 1860 census lists Martha as age 6, born in Virginia. But she is not listed in Floyd Co., VA, birth records.

Her death certificate records Martha Fyffe, age 66 years 7 months 29 days, born 25 Dec 1885 in Va, died 23 Aug 1921 in Morgan Co., widowed, father Joseph Slusher born in Va, mother’s maiden name Nancy Alice Wayed, born in Va, cause of death tuberculosis of bowels, informant Mace Cantrell, Ophir, Ky.

In the 1920 census she was listed with her son Early, as Martha Fyffe, 62, mother, widowed, b. Va Va Va.

1880 census of Elliott Co., Ky, Martinsburg precinct, lists as family #270:
Fyffe, John F., 31, farmer, Ky NC NC; Martha, 25, Va Va Va; Nancy A., 8, Ky Ky Va; Pilot, 4, Ky Ky Va; Cornelius, 3, Ky Ky Va; Oliver, 1/12, b. May, Ky Ky Va.

1900 census of Morgan Co., Ky, 5th magisterial district, enumerated 4 June, lists on p. 4A as family #53:
Fyffe, Martha, 44, b. Dec 1855, Va Va Va, farmer, married 29 years, mother of 11 children, 9 living; Oliver, son, 20, b. May 1880; Mary, dau, 15, b. Feb 1885; Robert, son, 10, b. Sep 1889; Marget, dau, 8, b. Aug 1891; Early, son, 6, b. Aug 1894; Nephi, son, 3, b. Feb 1897. All children born Ky Ky Va.

The next two households are their sons Pilate and Cornelius.

1910 census of Morgan Co., Ky, Paint precinct, enumerated 6 May, lists on p. 15A as family #194:
Fyffe, John, 61, farmer; Martha, 54, first marriage for both, married 39 years, mother of 11 children, 9 living; Melda, dau, 22; Seathie, dau, 18; Earlie, son, 15; Nephi, son, 12. All are listed as born Ky Ky Ky, although it is incorrect.

The preceding household is that of their son Oliver, and the next household is that of their daughter Alice and her husband James H. Cox, incorrectly listed as James H. Fyffe.