Even if he told you, it still doesn't mean that its true. Just look at the demos, its kinda obvious he isn't using "split screen" for this, because he is navigating through areas using both hands. I would guess, that the "observer thing" is made up just to support his defense if he gets caught.
Also, what you said above doesn't make much sense, placing observer in other base, doesn't help you a little bit. I think you meant, that he is using chase cam, but still that would require too much switching to make it work. Doesn't really fit together with the way he is playing.
One more thing jitspoe, you might want to look into ip adresses here. Their english seems to be on +- same level, so maybe check for multis? Not trying to offend anyone, just a precaution, they might just be real life of friends or something like that. Using another acc would the perfect way of trying to defend yourself, because you wouldn't have to answer any questions about the other acc which go caught.
Lastly,
WFG right back at you