Perhaps your local probate court can give you directions as to how to proceed (you don't say whether you have gotten information there). The house might go to auction for the taxes, or it may be be settled in the probate court. Here are some thoughts:
Someone, someplace declared the owner deceased...the county coroner? Can you obtain the document from the coroner and record the affidavit?
Is the deceased the only one on title? If the real estate is held as joint tenants with rights of survivorship the joint owners must agree before the property can be sold.
It doesn't necessarily follow that the son is an heir. Is he listed in the will? Is there even a will in existence, and if so who are/is the beneficiary/ies? Have you talked with the personal representative of the estate?
Another thought is that you might be able to get the house through the tax side of things, by buying the property tax lien (not just paying the back taxes, which would not give you an ownership interest).
I picked up only one property through probate and no heirs were found, so the probate court listed this house for sale via the MLS: we went to court with our offer. Sharon Vornholt is one expert on BP who may be able to direct you. You've done some good digging, but I am not seeing the entire picture...and probate is something that varies from place to place, so you need someone well-versed in your local statutes.
I found the decendants obituary from 2012. Researched and contacted who survived him.
The decendant is the only one on title.
There is no personal representative for the estate. The son doesn't want his name to be associated with the property in any way. He won't claim it and he doesn't want money.
The property has not been put up for tax sale yet, so, a lien hasn't been put on it yet. I'm attempting to circumvent that before it does which is why I thought of going on record paying the back taxes would be a first step.
In addition, the property is not in probate. It's basically an abandoned unclaimed property that has reached it's back tax limit and is subject to being taken by the city.