If your humidity is correct, the snake should shed in one full piece. If it hasn't come off that way and there are parts that are still stuck, you may want to place him into a warm water dampened pillow case and tie it off for an hour or so. He will slither around in there and the added moisture should help him slough off the remaining dead skin.
Next time he goes into shed use a spray water bottle and mist him at least once or even perhaps twice a day through the shed process. He'll thank you for it.