Joseph Thomas enlisted at Barrancas, FL, on December 30, 1864. He was mustered into Company B of the 1st Florida U.S. Cavalry on the same day.
He was born in Coffee County, Alabama, and was listed as a Southern refugee in his enlistment papers.
He died of fever on August 9, 1864, in the military hospital at Barrancas. I assume he was buried at Barrancas National Cemetery. You should be able to verify this by checking their website.
He was described at enlistment as being 5'7" tall, light complexion, blue eyes, light hair.