I have done some photo restoration in the past but it is timely and not enough pay for a single image. Look on YouTube for photo restoration tutorials....
Here is a quick 3 minute started to bring back some of the details. I just took your photo made a duplicate layer (control +J) then inverted it (control +I) and played with other duplicates to and their blending modes. This is not the final result but a result to help you see where you need to go. He doesn't look happy.
This image would be used as a reference that is all.
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