You have nothing to lose by calling the funeral director. If privacy issues prevent him from confirming or otherwise, he may be able to direct you to an appropriate party.
You might also try sending a registered letter via snail mail to the seller, giving full details of your suspicions and claim in a courteous way. If he hasn't passed away, he'll likely get back to you with an apology - if he has, then whoever is handling the estate will get it and should contact you.
Since this might also have the appearance of fraud, it might be worth contacting the Police with the information you have been gleaned and see what they might suggest. Perhaps contacting the seller's local Police station. I'm sure they'd rather advise of someone's passing than go chasing a fraud complaint.
If the poor seller has, indeed, passed away and his estate needs to go through probate, there will be a notice published giving sufficient details of the deceased for you to say 'That looks like him'. The notice will be inviting anyone with outstanding business with the deceased to contact the executor of the estate with details of the claim. I would send two letters - the first to confirm the identity - and if the reply says 'yes' then forward a second letter with all the details, documentation etc. of the claim with a request for your preferred resolution... ie - supply of the goods purchased or return of funds paid.
If your claim is validated, be prepared to accept whatever solution is offered.
Obviously there are other buyers out there with the same problem, so you might also try going through eBay, but since you didn't use Paypal and this would actually require them to do some work, don't expect any joy there. A PayPal refund is all too easy and anything else is all too hard.
Hope there is an answer in this for you..