May just be his way of processing. I have known children with autism to write upside down backwards and reverse...Mixing up facial features is pretty common,
I think it must have something to do with the ability to attend to faces...maybe he puts them sideways in the drawings, because then he feel more comfortable looking at them...Encourage more details or try to build stories around his pictures...

I recently had my little guys eyes checked by an optometrist and he has quite a difference between eyes. If there has not been an eye exam done, perhaps glasses are in order even though the school exams don't catch anything. If it works, then it might be how he sees the world - at least he is seeing people! :)

I can't answer that one, but I will say Joey tends to look at my face by turning his head upside down or sideways sometimes and seems mesmerized by looking at it in different ways?? And I do think our kiddos process things differently.. Could be nothing.. Just keep your eye on it and maybe by the fall if you are still concerned you can speak to his teachers.

Am I worrying for no reason? Does anyone else's child do this?