Do you have the authority to render this judgement, or has this been been made official?
It is automatically official, it never had to be "made" official.
If someone who was baptized Catholic goes to medical school, gets a license and then performs an abortion he is automatically excommunicated by Church law.
They don't send him a certificate telling him, there is no formal process. He did a deed which incurs excommunication and that's flat, end of story.
The Catholic Church is not ruled by British common law, but canon law. There is no presumption of innocence for people who violate the canons.
The only formal juridical act the Church can undertake regarding that person, then, is to restore them to communion if they repent in the proper fashion at some point in the future and petition to have the excommunication removed.
People are only formally excommunicated in writing when it is an open question of whether they have actually violated canon law or not - i.e. the law is not sufficiently clear in their specific case.
In Hitler's case there isn't any open question or doubt. He violated the canons openly, substantively and deliberately.