One source of that information is his obit in the "Confederate Veteran". I don't know what issue, as I just have a copy of the page, but it is the Volume for 1925 and the page number is 468. A look at the index should direct you to the issue.

It states, "He was at one time on the staff of General Wheeler, and also aide-de-camp to General Humes."

It also states that his U.C.V. rank for both leader of Camp Hardee and the 4th Brigade was "Commander". Again, as far as I have found, that is the highest rank in the U.C.V., but I certainly don't know much about the command structure of the U.C.V. The article refers to him as "General Oxford".