Interested in how a medium would know a specific detail.

Ok so I don’t believe in mediums or fortune tellers etc but my wife does. She recently came back from one and told me what the guy had said. There were some details that I have no idea how he would know. One of which was that when we bought our house there was an issue with the mortgage over a specific and not common title deed problem that we had to rectify before we could buy the property. This was 25 years ago and I have no idea how a stranger would know this or why they would think to even bring it up?