'Pushing' gave poor quality here -- there is not enough detail in the dark areas of his face for example -- and for a 'Portrait' that is what you want to see. His eyes are closed too .
Just an 'Old Bloke' whose been doing photography since 1951 !! Glad to advise ---PS -- I see you used f5.6 -- you could have opened up to f2.8 with that lens and still got enough sharpness for a 'Portrait' in poor light.
Great portrait! It goes against all traditional rules but it communicates emotion. I find that much more important than any technicalities. The closed eyes give a sense of intimacy and vulnerability. It took a while before I discovered the other 2 people in the background and they do add mystery and value to the image. Using F/5.6 was a good choice; with a larger aperture those 2 people would have dissolved.