Ok, this may be a bit of a long shot, but all the pieces fit. The old man is Mat Cauthon. I don't know how it could happen, but when he went through the Ter'Angreal, they could have created another him. He is a generally poor looking individual, except for the silk scarf on his neck. What does Mat wear on his neck, the scarf of course, although I am not sure if it is silk. Then there is the wide-brimmed hat, which is what Mat prefers, as we remember from The Shadow Rising. And finally, the part about thinking about what he could not remember. This is exactly what happened to Mat. He uses knives as well, just the way Mat does. I am not going to do it, but someone should go back and check what the people through the Ter'Angreal say to Mat, and see if it any of it relates to this.