Step 1: Delete all his saves.
Step 2: Kill all his companions.
Step 3: Kill a guard or two or more.
Step 4: Go to a different Hold and give away all his possessions including gold, just drop it all. [Or go to a Crypt/Dungeon and put it all in a chest that will soon reset]
Step 5: Go back and get arrested.
Step 6: Save in prison.
I am heavily confused with this logic
If he has his character, he'll want to play it still. All his stuff is lost though. Plus, if you've dropped his stuff... preferably in multiple bars, causing multiple fights, then most likely multiple deaths have ensued... causing multiple broken quest to be found later on.
If you delete his saves, he just starts over fresh. If you screw him over my way, the screw just keeps on turning.