You and your family have our deepest condolences. It is hard enough to come to grips with the chair that sits empty at Christmas dinner, but then to have to wrestle with the incompetence on top of it can be overwhelming. When I was 14, my father died from mysterious causes. It wasn't until after he was buried, we found out his doctor had misdiagnosed him.... the hard part is that no matter what you do next won't bring him back. Yet, you don't want this to happen to someone else at the hands of this person either.
I know how difficult this can be... our prayers are with you.