Is there any reason why he didn't deal with the seller directly using Localbitcoins or any other escrow trading platform of the same calibre?
Such a sad scenario could have been avoided because the escrow service first gets hold of the bitcoins even after the money is sent to the seller. Even if the seller refused to release the bitcoins, a dispute would resolve the issue.
I'm not sure he knows about that, but after he claimed he paid the seller after almost an hour simply because the blockchain transactions has been very slow all day long and he wasn't anticipating a foul play.
Great lessons are sometimes learnt the bitter way, I'd say.
Thanks to everyone!