Jodene, it might help a little if I jump in here and clarify the identity of the William A. Thompson who is linked to your ancestor.
There were two Clark County men named William A. Thompson who served in the Confederate army.
The first was William A. Thompson, born c1832 in Georgia, a schoolteacher, who enlisted in Co. E, 2nd Arkansas Mounted Rifles, at Camp McRae, Osage Prairie, Arkansas, on July 27, 1861. He was wounded and captured at Murfreesboro, Tennessee, on December 31, 1862, and reportedly died of his wounds before he could be sent to a POW camp. He was posthumously named to the army Roll of Honor on October 3, 1863, for his heroism at Murfreesboro.
The second was William A. Thompson, born c1845 in South Carolina, a farmer, who enlisted in (1st) Co. H, 23rd Arkansas Infantry (the same outfit as your ancestor), at Arkadelphia, Arkansas, on March 6, 1862. He was captured at Port Hudson, Louisiana, on July 9, 1863, paroled on July 10, and exchanged in Arkansas later that year. This man survived the war. He applied for a Confederate pension from Clark County in 1916 (Pension No. 22301) and died in 1932.