I'm wondering if this is the same John B. Kerlin who was the son of Arthur Kerlin and Martha Lyle, who both died in August 1868. Martha had been married and widowed before she married Arthur. Her first husband was John Young Shuck, and her son by this marriage, William Andrew Shuck, was my great-great-grandfather. William fought in the Civil War and took his siblings and half-siblings as his own family after his mother and step-father died. They lived in Fulton County, Kentucky.
John B. Kerlin who was a member of this family was born about 1851 in Kentucky. I'm finding census records for a John B. Kerlin, born Kentucky in October 1850, wife Stella, children Stella, Mary L, and Edwin A in Louisiana. I haven't found a marriage record yet.