but whether an online obituary that seemingly anyone can create is sufficient proof or not.
The question here is why does someone have to create a fake obituary? I don't see any effect when someone fakes it

I suppose this obituary is fake, then everyone believe that Bruno died. As soon as Bruno's account was active and posting, people reacted violently to it. What are the benefits of fake obituary? Who will benefit from counterfeiting it? Nobody, I just see the disadvantage here, so I suppose no one tries to fake it without any benefit, am I wrong?