You know, if I were just basing on the sketch, minus the gait, plus the raspy voice, I would conclude that the face and voice looks incredibly similar to Smith-Magenis syndrome. But, 75% of people with Smith-Magenis syndrome have low IQ, and YBG is not the case. However, the chin, the square face, small eyes, widely set, and the voice. I know it is not the case as they have other behaviors, such as nail-biting, or self-mutilation. But they say there may be isolated mutations on chromosome 17 that fly under all radars and present much more functionally, but the looks are the same.
I don’t want to link the faces as they are all good people. But one can Google - look at adult faces, there are videos with voices, too, these people don’t speak well (low IQ) but the raspiness and the manner is spot on.
However, I would not be surprised if the person can mimic the voice, the gait, whatever. He is smart enough.