Ear infections are common with autism and consistent with moderate hydrocephalus, which might be a sign of cerebellar dysmorphism. Increased intracranial pressure can distort the shape of the skull making it slightly bigger, leaving extra space for infectious bacteria, especially with exposure to water. DWV also results in the ears being placed slightly lower than normal (or maybe the rest of the head just looks bigger).

Your friend should definitely see an ENT to get any infections cleared up, but an MRI wouldn't be the worst idea, either.