I don't see any way to use a one piece split coupling to make this repair. The one I linked to, is a two piece and will be stronger than the original coupling. I would ask the inspector to use 90.4 to permit the repair with the two piece split conduit. It comes in 10' lengths, just cut it in half and bolt the two sections on the conduit centered on the old coupling. The hardest part would be removing the only threaded coupling. You can split it with a saw being careful not to cut too deep into the existing conduit. I would not remove the only coupling unless the conductors were locked out. You will have to check and make sure there is no damage to the conduit that has left sharp points that will damage the conductors after the repair.
"It is the first responsibility of every citizen to question authority." B Franklin