I had the same problem for many years....(NOT!)
Either your friend unconsciously feels others dont take him serious for other reasons than his looks and doesnt realize it, or others are not taking him seriously because of the vibes he gives off. I've known guys that intimated others with their looks and physique, but thats different. I've know girls that werent taken seriously because they had huge boobs, even if they were real. But if this is true of your guy friend, he just needs to take up MMA and get his face roughed up a bit. Minah