I've honestly never trusted these guys who claim to speak 30 distinct languages. Can it all be tested at once?
And that softer requirement is also not cheating. If you speak many other languages you even need to reactivate your native language.
It's reasonable to ask what a person means when they "speak X languages", though. It's in itself more vague than one might think. If you ask a monolingual person he might consider a C2 (European Framework) level to not be "speak my language", while a language learner might consider a barely passed B2 and then never used again as "speaking that language".
I speak one foreign language at a solid C2 level, but I also scored in the 99th percentile on the GRE verbal (USA's English Language grad school entrance exam for native English speakers). I never feel fully fluent in that foreign language, even when I can pass language exams most locals can't. There's simply to way for me to match my fluency and comfort with English.
So I agree; the standard for fluency is always relative. And -- contrary to superficial appearance -- even native speakers have a wide variety of levels of competence and you can always benefit from studying more.
That said, it's certainly amazing what he can do. He taught himself Italian over the course of about a month, simply to read a single dissertation written in Italian. He spoke French already, and he asked me a few questions because I'm fluent in Spanish, because when he didn't find a word in his Italian/English dictionary he wanted to make a guess based on other romance languages. I think ultimately he wouldn't even consider himself at all competent in Italian, even though he was able to read doctorate-level writing for a few weeks.
"If..., then..." and "I've spoken English for decades."