My first question would be to find out if there are any pictures of him prior to 4 years old. Second would be to match any birthmarks.
The more I look at the picture, the less I think it's him because of the shape of the nose and the color of his eyes. However, the pic that was posted of the man is from a webcam, so it's mirrored, right? He does have a freckle on his cheek (left, looking at the picture) that matches the freckle that is on the four year old picture of Michael (right, looking at the picture).
Also, my friend has a son whose eyes lightened a lot from the color they were when he was four. Another friend showed me a picture of himself at about four and the nose he has as an adult is significantly different than it was as a child, so it is also possible for facial features to evolve drastically from childhood to adulthood.