Was this a scam?

My parents sold their home to one of those ‘we buy houses’ investor guys. He gave them about $6k and recorded a deed into the new owners name. It wasn’t him on the deed. We told him the house had a mortgage and that it was in default and could be foreclosed on soon. He said he would pay it off. Well he didn’t and the house went into foreclosure and was sold. At some point a new tenant moved in and while I don’t know the details of that arrangement this guy had a family, had paid a deposit to this investor guy and begun making monthly payments to him. He was making repairs to the house and was planning on moving in his family soon. We told him something was off about the investor and that the foreclosure could happen soon. He didn’t listen to us. I can’t figure out what the end game was that this investor was playing. Was he scamming us or this other family? Has anyone heard of this sort of scam before?? Thank you.