My husband found out he has a property under his name without his knowledge. Don't know what to do?

Other answer:

Real property – real estate? It sounds odd that he would not know so, it is probably someone else with the same name. If you search names in the county records, you would be surprised at how many duplicate names there are – a good idea to use your middle name or initial but, it is surprising how many people don't do it.
and he found this out how? he needs to find out from the county public records if he in fact is the legal owner and if he doesn't want it, then put it up for sale, he is the legal owner
Nuff Sed:
It may be a simple scam of some kind or a complicated mistake or even a criminal fraud. It is not difficult for a criminal to forge a notarized deed and have it recorded, thus appearing to transfer "title" to someone who may have no knowledge that this has occurred and without any knowledge by the actual owners.

I have one of those in my chain of title and it caused havoc for the people who later sold me the house after spending a year in various courts.

He can rent it out or sell it.
I'd think the first thing tooo do would be to find out when and how it got there.
D R:
how did he find out he has a property in his name; is there a home on it, if so is it occupied?
All actual owners of any property have a title deed and it is registered at the county registry offices.
All owners of property have a property tax bill mailed to them each year. If those taxes go unpaid, the
city will sell it for the taxes owing.
Go to the county registry offices and look at the records.
sell it, rent it out, make sure the taxes are paid up
Then the property belongs to him
The Oracle of Omigod:
He needs to find out who sold the property and find out what is going on. A person who used his identity to buy property may be planning to steal his identity for other things or may be a criminal.