I’m going to suggest he died and was dropped from the rolls of Company E during the period November-December, 1862.

This based on the fact that the muster roll for this bi-monthly period is missing from the records. He is noted on the Sept/Oct, 1862 muster roll, but is not noted on the subsequent roll in the records, that covering the period Dec. 31, 1862 to April 30, 1863.

.........

Columbus G. Law, Private, (Old) Company E, 1st Regiment Alabama Infantry,* enlisted June 30, 1861 at Camp, Ala., Fla. by Col. Clayton, captured at Island No. 10 April 8, 1862, forwarded to Camp Butler, Springfield, Ill., left Cairo, Ill., sick, October 25, 1862 en route to Vicksburg, Miss. for exchange, recorded on October 31, 1862 as “absent, Re-enlisted, not yet exchanged,” his father Wm. Law, filed claim for the settlement of his accounts March 29, 1864

* This company subsequently became (New) Company E, 1st Regiment Alabama Infantry

M311: Compiled Service Records of Confederate Soldiers Who Served in Organizations from the State of Alabama