I have a slightly different take. I dont think comparing Biden to Santos is quite Apples to Apples.
Santos, much like Fauxcahontas, simply appear to be flat out liars. They used faux heritage to further their careers. Although in Santos case, his family could have converted to Judaism at some point. But you sure arent converting to Cherokee. All of his other lies though really make this a moot point.
Biden, I think, is in his own world of delusion. Not knowing what is actually the truth. I really dont think he has the mental capacity at this point to even understand what he is saying. Or claiming.