I don't believe HIPAA extends to autopsy reports in cases like this. Emily Glass' autopsy report was made public. She died by gunshot to the head, the weights of her organs, bruises on her body, even the striae on her belly were included in the autopsy report that was made public.
I think Jon Benet Ramsey's autopsy report was before HIPAA? But the autopsy of a little girl was made public, including details of her genitalia and possible signs of sexual abuse noted by the ME.
We are not just talking about case and manner of death, we're talking about a full body post-mortem examination by a medical examiner/coroner.
It's not the same as the notes that are made during the autopsy, it doesn't include things like "after doing a Y-incision I found ..." But there's no privacy for the deceased in it.