This may be a start. I did not find Isaih, but I did find Isaiah Whitmire. Click on the link below which will take you to the home page of Tom Leatherwood, Shelby County Register of Deeds. Go to the right side of the page to the section "Archives". This section has death and marriage records for Shelby County. Click to bring up "death" and type, in the appropriate box, Henderson, Isaiah. The site will show you an actual copy of the death certificate. The site can also be checked for others you are searching in Shelby County, TN.