Legal Question in Medical Leave in Illinois

Unfortunately, you're dealing with the privacy rules of "HIPAA". There are a lot of misconceptions about what information can be released and many doctors don't even understand the law. And if you didn't talk to the doctor him or herself but to some office staffer, it is highly possible that person wouldn't understand the law and simply have given you the "standard" reply. One exception is for medical information about a deceased individual where that individual's medical condition may have a bearing on your own medical condition (or in your case on the deceased's grandchild's medical condition). The grandchild's doctor should first put in writing that the information would be relevant (presumably because it is genetic but only the grandchild's doctor can explain the need medically). Then the request should be resubmitted to the deceased's doctor. If that doctor still won't release the information, an attorney should be able to write a letter specifying the exception. If all else fails and the information is that important, you might have to open a probate estate for your mom and subpoena the information, but hopefully it wouldn't have to go that far.