This wasn't the passing of a beautiful dog, this was murder.
If I had a family like that I would shoot the lot of them. I have had german shepherds and rottwiellers since the age of 18 and if anyone even my own evil grandmother had treated a beautiful dog like gangster, the way your family did I would have killed them.
I am so sorry for your grief and there are no words of condolences, just one day plot your own revenge for the attrocities they bestowed on your lovely boy.