Ok, to answer some of the questions. 

He wanted a refund for everything, including the upgrades. Which of course I'd happily give once receiving the item back. 

He opened the Return 3 days after it was sent and while the item was still in transit to him. He live on Norfolk Island so there will obviously be a slower than normal delivery time. How it's possible to open a return for an item which hasn't been delivered is beyond me.
Ebay said they closed the case in his favour because the item hadn't been delivered, despite the back the tracking clearly showed it was in transit.

I have just spoken to Ebay again on chat, with no luck. I might try the phone option as has been suggested. The whole situation is extremely frustrating and stressful.