Can you help with style advice for a male friend?

A good friend of mine could do with some style advice. He has quite a long face, and a pale skin. He has gorgeous blue eyes and bushy eyebrows. Currently he wears his rather fine hair, in a middle path and shorter on top with length at the bottom. (A mullet). It has no body or bounce and just sits on his head.

I am not great with mens fashion. Is the Mullet in fashion? He also has grown his sideburns quite long and thick? I feel the style is making his long face longer. So mostly I think this is about hair. His hair is very very thin and fine. I suggested a shorter messy cut. Any photo’s or tips welcomed.