No telling but the fact he would not meet you nor was in the vehicle that was offered for sale when you drove by the house tells there was something afoot.
A lot of these folks are just plain shysters. They have no problem wasting other peoples time and then do a bait and switch or try to convince you to accept something less.
It took me close to 5 months to sell my last private party sale vehicle and it was not because it was not price correctly. Selling through Facebook Marketplace is a colossal waste of time for me and Craigslist has it's pitfalls also.