You have good rapport, probably the hardest part and the most important. Emotion and expression matter more than technical details.
There are a few technical details worth considering.
Lines in his neck don't add to the image. We are also getting more of the inside of his nose than we need. Having him project his face forward and getting a slightly different angle would help solve both.
The light is coming in from too low. It isn't to the point of "horror movie under lighting." Still, we generally look better with light coming from a higher angle. It would also be good to get nicer lights in his eye sockets.
You might want to improve the color balance so his skin looks more flattering.
Like I said, you've already nailed the hardest part. My suggestions are just technical details which will give a more professional touch. Keep it up!
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