I'm not sure why your grandfather is listed in the wrong county. I went back to check and he is indeed listed in Tallapoosa Co. The original source is:
State of Alabama. Index of Vital Records for Alabama: Deaths, 1908-1959. Montgomery, AL, USA: State of Alabama Center for Health Statistics, Record Services Division.
I notice that Tallapoosa and Elmore counties adjoin, and that Tallassee is right on the county line, separated by the river from East Tallassee in Tallapoosa Co. I wonder if the hospital's records department is in East Tallassee. Or maybe the records for the two counties were submitted together to the State Center, and the transcriber made a mistake.
As for John's middle initial being wrong, that isn't too unusual. I would bet there is a stray mark on the record right below the rounded capital "A", and the transcriber mistook it for a "J".
I notice that I didn't have R-numbers for James and John, which means I didn't connect them with your family. Thanks for pointing that out, especially since I didn't have John's death information in my database.