My aunt lives in a house that sits on my grandfather's land, on which he built a house over 20 years ago for my now deceaced grandmother. My aunt paid him $4000 in the mid 90's, and has paid the taxes and utilities since. The taxes are in her name, but the title was never transferred into her name only, my grandfather's name is still on it and she does claim a homestead exemption. They were both behind on taxes this year, and in order to pay his portion of the tax, he sold her house without telling her. This was also on the day she paid her portion of the taxes. She got a letter from a man who told her to be out on December 1. My grandfather told me this past weekend her had no choice, because he had to pay or they would take the land. Her also said "It's her house. She bought it". Who is in the right?

No she did not buy it, all real estate contracts have to be in writing in most states. Next there was no bill of sale, no deed transfer no nothing.

Merely paying taxes is just paying the taxes of someone else, unless bought at a tax sale.

Also they will not take you house if you are just behind one years taxes ( at least normally) So if the grandfather is on the deed, if no new deed was ever done, if there was never any legal sale of the property, the aunt has little legal claim.

From a moral standard, yes she has a right, but law has nothing to do with moral right, I doubt her claim will stand up in court