Demarry, E. L., Pvt. Co. A. Crescent Regt. La. Infty. En. Sept. 13th, 1862, Camp Moore, La.
Present on Roll for Jan. and Feb., 1863. Roll for May and June, 1863. Absent. Taken prisoner at
Camp Bisland, April 14th, 1863. Roll for July and Aug., 1863, Absent at Abbeville, sick.

Demany, E. L., Pvt. Co. C. Cons. Cres. Regt. La. Infty. En. Sept. 3rd, 1862, Camp Pratt. Roll
for Jan. and Feb., 1864, Absent without leave since April, 1863. Deserted.

I see that he was convalescing in Abbeville. According to the bio you posted, that is where he lived. Might be a good indication it is the same man. The Crescent was consolidated with the 18th for a short period of time which would explain his association with it. I don't know why his record shows enlistment at Camp Moore; his CMSR clearly shows that he enlisted at Camp Pratt. It appears he never returned to the Crescent; maybe he joined the 7th Cav as suggested?