If he did a bank money wire (is different than direct deposit [ACH] - that can be reversed), chargeback isn't an option.
If the escrow service has received the funds and has not releasing the funds yet to the buyer, then he may be in luck ... they should make the escrow service aware the item is stolen and pester them constantly - with some luck they may acknowledge its stolen - once they do that, the buyer may, though a longshot, have some reasonable grounds for filing a lawsuit against the escrow service; especially if they are not registered as required in some jurisdictions.
Lastly, depending on the amount involved (say $xx,xxx), the buyer may want to contact an attorney pronto and work to get a court injunction to prevent release of the funds to the seller.
Good luck.
Ron