As he has recessed eye sockets and you use a butterfly lighting, some fill coming from bottom (a reflector, e.g.) would have help to get at least a catchlight. For the deep shadows, it is up to your style however. May be try to make the backlighting more subtle too, if possible. Just my two cents.
I think he has a good potential as a model. You could you ask him to get dressed with something more elaborate that a white t-shirt, for example. You might try different poses as well. You might try to shoot from a slightly lower level, not higher than his eyes, to give him a more powerful appearance. Just few suggestions
Disagree. Height is fine as seen from the shadow under the nose. And as far as we have no clue about the size of the lighting source, there is no way to say it is far or close.