Which one's Nathan?

Nathan's grandmother is in town visiting and brought old (very old) family pictures. Everyone wonders who they get their looks from. Well, we found where Nathan gets his. His great-great uncle Oscar. They could be twins, it's kind of scary. And for those of you who know we have a ghost in our house, we are beginning to wonder if it's uncle Oscar. :) If you can't figure out which one, he is on the back row, second from the left.