Your idea about the measles or maybe a war wound could be a real possibilty and is the most realistic theory I've heard so far. He did not have a brother John. He did have a brother Armstead L. (A.L. Barnes 1843-1923) that served in Co. F 1st KY Cavalry CSA. I've ordered and installed a military marker for him. He's buried in Star Cemetery in Harvey Co., KS.