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.
Interestingly, this is exactly what happened to me – luckily I did not need tubes, but it could be surgically fixed.
I was also diagnosed with autism, but am on the low end of the spectrum – I barely qualify as asperger, and while it was bad in early middle school (just using violence, hitting heat against walls, etc), by the time I finished high school, it was not diagnosable anymore.
Your friend should definitely see an ENT to get any infections cleared up, but an MRI wouldn't be the worst idea, either.