Yes, but we have to understand the difference between not being a nice person and breaking the law.
1) "The Germans treated Jewish prisoners poorly." Sure he supported this, but he was not in control of any prisons and did not instigate any laws to their running.
2) "He asked Hitler to be mean to them." I am pretty sure I could mail my PM and ask them to "deport all the juden", I don't think I would be arrested, and I definitely would not be considered to have committed crimes against humanity.
3) "People mistreat Israel". He has been dead for a hundreds years. You cannot charge him with Iran developing Nuclear weapons or Palestine hating Israel.
For the most part, you are accusing him of thought crimes. Things that cannot be used to declare him an official war criminal or to have committed crimes against humanity. Sure we could easily charge him with having committed thoughts against humanity, but there are no laws in place to prevent your heirs from profiting from your horrible horrible thoughts.