William F.B. Grigsby, "French", was born about 1837 in Clark County, Kentucky. He married Mary E. "Mollie" Bright before 1860. He and Mary are enumerated in Liberty, Clay County, Missouri in 1860. In 1870, W.F.B. Grigsby appears in Franklin township, Bourbon County, Kansas, boarding with the F.M. Smith family. He is listed as a merchant. Mary does not appear to be staying with him, but he may have been away from home to conduct business.
In 1880, they are in San Bernardino, San Bernardino County, California. He is a Storekeeper. They do not appear to have had any children. And right now the trail has gone cold after 1880. They both may have died in California, or they could have moved to another state. Hope this helps.