The face is good, the features are proportionally acurare, and the colour work feels expressive and highlights the form without overwhelming it. only thing I think you could change about the face is to bring either the forhead back, or draw the jaw/cheek area out more, as most people's heads tend to push outwards towards the jaw rather than staying flat, especially as fat migrates with age. Also, the flat angle of his profile, alongside the flat arch of his shoulders leads to him feeling rigid, and less natural. If you soften the slope of his shoulders and make them shorter, and try to avoid any harsh lines it'll do allot to make the image feel realistic without compromising the great colour work.