CSA stand for Confederate States Army, or Confederate States of America.

What kind of information do you have that indicates that he was a POW? If all you have is a statement that he was paroled on June 6, 1865, then he most probably was not a POW, but was simply paroled when the war ended. When the war was over, all the soldiers at that time had to report to a Union unit, and turn themselves in and agree to quit fighting, at which time they were paroled and sent home.

Would you be any kin to Lt. Layne Romagosa of New Orleans, who was killed in Viet Nam?