Consider his location, and the actual fuel he is forced to buy, not by choice, but by supply and location....
Id say he is getting acceptable miles per gallon based on this..
You can't base mpg generically on "gas", as some places fuel is pretty damned poor.... buy gas in south america, and ride hard.... you might get 20 mpg...
Mexico? Maybe 25 mpg...
Ohio? Well, we have ethanol, but get 40 mpg....
I do think proper carbs and airbox, along with airfilter, and tuning would net better... but he's running carbs currently that are smaller in size, with pod filters...
Both effect mileage, and drastically at that, his carbs are having to run in "acceleration mode" for much more of their life, just to give acceptable performance, which still is degraded... it isn't like rolling along in "eco / cruise mode" as a larger carb size would provide..