Can an elderly illiterate person deed property to one child without any family members knowledge of the transaction?

Wife name should be on the title to house, but even if it wasn't, the Probate court will not allow the house to pass to any kids....spouses have firm rights that take precedence over kids. In my state, for example, you can disinherit your kid (s) but state law prevents disinheriting your spouse. Better get help from a lawyer, this sounds more complicated than an informal probate.

If The property was owned jointly, then she would have needed to sign off on the sale for it boot be valid.

Your situation has to have an experienced attorney to get through this & ASAP.

There are things you can & should do on your own now:
find all their wills & any codicils to them; do a "face sheet" on your parents with all the important details like DOb, marriage date; all kids DOB even for kids who have died (even infant death); details on all real property ownership. Also you should get all items filed on the property (this will be the parcel # and will be on their tax assessor bill) from the courthouse. Most courthouses have the past 5 -10 years available as a download for minimal cost. Like maybe $ 5 for a deed of trust or $ 8 for a covenant. For filings older, the courthouse researches & snail mails to you. You want everything on any property owned by your folks. Either you can do this and make copies & give to your attorney OR they do it and bill for their & their paralegals time. All this is open, public records too.

The daughter that is the named executrix should take the lead on all this with the probate attorney but you certainly can help with the leg work & organizing for her.

esquej2, in order for parents to quitclaim a property over to another person, BOTH owners of the property need to sign and be notarized. It doesn't matter if neither or one cannot read or write [illiterate], they can sign an X as their signature. Since only one owner had signed, chances are that quitclaim is null and void. An attorney will sort this all out.

In a normal course of events, if a husband and wife own joint property, said property would go 100% to the surviving spouse, or 50% with the other 50% going to the children.

It always amazes me how many people think if one parent passes on that the whole estate gets divided among the children.... what will the surviving spouse have? Nothing?

So the elderly gentleman gave away his share of the property and then wanted it back? Oops too late, wrong decision, too bad. However, the widow has some rights here which depend on state law. She needs an elder law attorney to sort out what's going on for her. The other kids can help her but ought to butt out if the fight. Now, if the now deceased old fellow was mentally incompetent at the time he signed over the property maybe there's a case to be made. But it may be hard to show he was legally incompetent now that he's dead. Now everybody needs a lawyer. The widow needs to act. The siblings should decide if it's all worth it, financially and emotionally.