Unlike most occupations, clinical medicine is not an exact science.......the human body an psyche makes sure of that.
There is no law against against wrong or misdiagnosis, it happens everyday in every hospital and if there had been a law, then the prisons would be full of convicted doctors.
All doctors in Clinical medicine ay some time in their professional career have made errors in their diagnosis, some minor and others,as in this case, tragic and fatal.
FredPuli is correct, one would need to show and prove negligence in the misdiagnosis of this case and call into competence or lack of it, that of a doctor or nurse who's qualifications and expertise should have acted differently.
I do indeed feel true sorrow for the victims in this case, but also the medical and nursing staff will also feel devastated.