hahaha... ****er..

The guy's a nut, you don't have to pay anything but the repair. I personally would never lend anyone a kite, maybe some of my friends. If I did however, whether it's a friend or a complete stranger If something happens to it, I would expect it to be returned in the same state it was. In this case, a repair would see to that.
I wouldn't expect to be handed a new kite. **** that, offer him you will pay the repair and if he doesn't want that you don't have to pay anything. It's not a negotiation, it's a friendly offer from you. Simple, take it or leave it