UPS should not be to hard to file a claim on. I used to do it for a living many years ago, and it was an easy process.
I could not tell by your post how many times this item shipped, but it sounded like the shipper sent it twice. That might be a problem.
If he sent it the first time, they damaged it and returned to him, it would be his job to file a claim for damages.
If he then fixes the box and re-sends it to you, you cannot prove that the second shipment caused the damage. Mostly it's up to the person who first received it damaged to file a claim.
Also, was there any insurance on the package? I know UPS has $100 of insurance automatically on any package, so if you had no other insurance that would be the max you could claim.
They probably have info on their web site about how to file a claim, but if the shipper had an issue w/the first shipment, he needs to do the claim with the original shipping numbers.