There is a follow-up blog by Jason Fung from the one quoted earlier ...
https://intensivedietarymanagement.com/medications-actually-work-type-2-diabetes-t2d-40/
Basically, what he is saying is that Type 2 diabetes is a problem where there is too much sugar in the body (not just the blood), Drugs like sulphonylureas and insulin lower blood sugars, but don't remove these sugars from the body. Hence they tend to increase weight as the excess glucose is stored as fat by insulin. This then causes long-term health problems such as heart, liver and kidney disease. Drugs which help eliminate this excess sugar have significant benefits to life expectancy.
However, the simplest way to get rid of this excess sugar is to reduce the amount of carbs we eat and to burn off the excess sugar (fat) by intermittent fasting. Lowering blood sugars will lessen the likelihood of diabetic complications such as blindness and neuropathy. However, most type 2 diabetics die of heart disease and the just lowering blood sugars does not reduce the likelihood of heart disease, but reducing the amount of accumulated stored sugar in the body (e.g. liver fat) does significantly increase life expectancy.