It went into parole camps ca. August 23, 1863, where it was to drill and re-equip until exchanged (i.e., swapped for a like number of Federal prisoners in Confederate hands).
It had a grand and glorious second-half of the war, serving in some of the most famous engagements of the war.
This is what I have on Sampson Stafford:
"Private Sampson Stafford -- AWOL most of career with regiment; 1-2/63 “forfeits all pay to date & allowances” for AWOL; 7-8/64 absent “in arrest” awaiting general courtmartial (presumably for AWOL); no further data"
I have never found data on the courtmartial, but he clearly never served with the 43rd after 8/31/1864.
Wish I could help you more. -- Jim Huffman, Co-Historian, 43rd MS Infantry