Returning damaged item to seller....

Insurance is the business that works ideally if no claims paid at all. When it's time to pay claim the immediate denial is the usual outcome if you have no attorney or attorney fees are not reasonable with loss.

PayPal did reimburse my cost for item and shipping.

Seller still has not replied to my offer to pay 1/2 return shipping.

I will hang on to item in case he decides he will also pay 1/2 return shipping.

He should pay for shipping imo; however, be aware he’s more than likely out all the money, plus the money it’ll cost to get it shipped back and end up with a broken item unless he had the shipper pack and box because insurance won’t pay for damage.  
 

So maybe cut him some slack.

Just keep in the back room, it may take awhile. You owe the seller nothing, much less ANY return shipping cost. I’ve been buying and selling online for over 21 years. As a seller, I had to learn the hard way, don’t feel sorry for the guy. Guess I missed the part of your post that said you got the cost refunded. You are much more than generous, no one has ever offered to pay half of the return shipping!