Echoing what Jim Huffman has said - his capture at Williamsburg, Virginia in 1862 should have been documented by a Federal record of capture describing his transfer either to a Federal military hospital or Federal military prison. These will appear in his Compiled Military Service Records. You need to get a copy of his CMSR from the National Archives, or through the Military Records Service that contributes to the support of these message boards. I don't see the Records Service link on the boards this morning, so contact Webmaster Jim Martin and find out what happened to it.
You asked: >>> Regimental reports have him as "Absent in the hands of the enemy" until Oct 1862 Nov 1862"Absent sick at Richmond, does this mean He was exchanged. <<<
Yes, assuming the Company Muster Rolls reporting him captured in May 1862 are correct about his being "in the hands of the enemy." I checked the Fort Delaware Society database. We do not have his name (unless it is misspelled), but our records for 1861/1862 are not complete.
The Dix-Hill Cartel [a general exchange agreement between the two War Departments] was signed July 22, 1862 and resulted in the immediate parole and delivery of all prisoners being held to their own side. The military parole was the captive's personal promise not to take up arms against the United States (or the Confederate States), and not to perform any war related services on behalf of their own government until properly exchanged. They were delivered as "paroled prisoners of war" and after a detailed exchange accounting process [POWs were traded man for man, or equivalents] were individually declared exchanged and returned to duty. Any excess on one side or the other remained in the status of a "paroled prisoner" until some future exchange accounting cleared their names. A mass movement of prisoners took place in August and early September of 1862.
Thereafter, per the Dix-Hill Cartel, all prisoners were to be paroled and returned to their own side within ten days of capture, or as soon as practicable thereafter. This was pretty much adhered to through the end of June 1863. Had the Union government lived up to this aspect of the exchange agreement after July 1, 1863 and throughout the balance of the war, the horrors of Andersonville and Salisbury would not have come to pass.
Fort Delaware Society