Nephew has odd-shaped head?

It looks flattened from front to back and literally looks like he is about to sprout frills (like a triceratops) on the front of his cranium. His head is huge to begin with and he sleeps a lot on his back. Did I mention that the back of his head is flat as a board. Should his mother take him to a doctor? I've heard of helmets that can "re-shape" the head, but there is a narrow window of opportunity to do this.