It appears he was discharged, then why was he captured?

George there were several being at least 3 or four Confederates who had been discharged from the Confederate Army and yet were arrested and taken to Camp Chase and died there. And this would pose the question how many were discharged and did not die at Chase or other northern prisons?

All the ones I know about were from the States of West Virginia and Kentucky and Tennessee.

For whatever reason the Union believed them to be a potential threat and had them arrested as soldiers of the Confederacy.

And to make matters more complex it depended upon the reason for discharge. Was it to be discharged from one unit and then enlist in another?

The one from West Virginia had a medical discharge as he had lost the use of his left eye yet upon going home he was arrested and died at Chase.

Perhaps a Union neighbor or the border Union guards had saw him in a Confederate uniform at one time and that was enough to cause he arrest or perhaps he had misplaced his discharge papers, who knows? As we know things happened in the war that were not supposed to happen.

The soldier from Tennessee had been a Captain and I saw his discharge papers on fold 3. He resigned and went home yet he was arrested at his home and taken to Chase and died.