It seems that according to B-ultrasound, it can be identified whether it is a new injury or an old injury, and it is best to provide direct injury identification. You can make another appraisal, but it's good for you to have a different conclusion. The first time was a settlement, no judgment, out of court. The second trial should provide new evidence to prove that the injury was not caused by your husband. In addition, if there is only the result of injury, and there is no witness or other evidence, it should not constitute a chain of evidence. It is best to find a witness who witnessed the incident. You can find a lawyer to investigate your husband and sister's case.
It's just a layman's opinion. Please listen to the lawyer for detailed questions.