Yes, this needs to be straightened; it doesn't look intentional or help the photo in any way being tilted. Also you are chopping him at his feet which is generally a portrait no-no.
But I like the long exposure idea with the train and think the photo has a very rich mood. I agree too with the other reply, I would fill in his face in a teeny bit too. You could maybe pull up the tone in PS.
Nice shot.
One more thing: If he isn't homeless or involved with the Rescue Mission, I would take that out. I think anyone who looks at the image is drawn to reading that and it 1) takes attention away from the subject and 2) people will try to form a relationship between the sign and the subject since it is so prominently placed.