find out what the deadline is to file a paypal claim. I think it is 6 months. As long as he is not pushing you past any deadline, be patient.
I ran an ebay business for years, sold millions of $ of merchandise, and never lost a dime on US sales (some european sales went missing in customs). I had guys disappear for a time and found out they were in the hospital, caring for a sick loved one, or just on a long vacation. I had one lady pay me for a $1500 item and it came back undeliverable. I tried for years to contact her and never did. I assume she passed.
Jerry