It's funny to me that people act like losing weight is some highly, specialized skill you need to study over years to be able to pull off. Buy a kitchen scale, count your calories, start moving, estimate the calorie loss from that. Stay at a slight calorie deficit so your body has to burn reserves for continued operation. No magic involved. If you want to be healthily losing weight, make sure you vary your food (that sounds obvious but many people who are fatties often have not a good relation to and education about food so they literally do not know what's good for them) and also make sure you lose it at a healthy rate. It's not rocket science. There are endless resources on nutrition. In non-terrible countries most food packaging will also tell you what (and how much) you are eating.
It does take discipline though, especially not going back into it. Eating is fun.
I have not followed this man and know next to nothing about him, but if he did this on purpose he's a complete psycho.