Not sure, but I think it's a journalistic convention. Since the person was not generally well known, the quotes indicate that it's something others who do know him say. They're not being sarcastic.
Yep. Newspapers have developed a kind of shorthand to deal with the tight space constraints on headlines. Putting a description of a person in quotes is short for "who has been called…".
But also, using quotation marks purely for emphasis/sarcasm is an informal practice, it doesn't belong in something like a news article (or an essay, legal document, etc. ).
Yes, but whether someone is brilliant or not is usually an opinion, and as such should not be stated as fact in news to the general public with almost no exceptions.
People like Einstein are the only ones who get the exceptions, and I don't mean any disrespect but this guy was simply not Einstein.
