For what it's worth, I do not recall finding any substantive information about Withers at Mobile when I was researching the Confederate defense of that city. My recollection is that his name is mentioned a few times in the fall of 1864, but I do not think he was involved in any meaningful manner in the final operations on the Eastern Shore in early 1865. The 1st Mississippi Light Artillery Regiment was assigned to the Mobile defenses after its exchange, but I do not recall that Withers commanded it.