who is this young man in Tyndall Bon Homme Co SD

I found this in Tenn. And about fainted !! What is strange is that this yound man looks just like my son-in-law. "Sean" Even Sean wife,mother,father, brother& sister and his own children all thought this young man was Sean. This is Sean's TWIN even to the color of eye's hair face nose lips chin and body biuld. It is kinda scarry and neat in the same breath. Would really like to find out who he is. I think time of photo is 1880 to late 1890. They say eveyone has a twin !!!

taken 1880 to late 1890