If a 12-year-old weighs this much, then the parents are not only incompetent, but they are abusive as well. Parents should be providing fresh healthy food and encouraging exercise. There was a case in my area where a child was removed from the parents because their child was this obese and the parents would not change their lifestyle. A child this fat has a terrible life and is ridiculed daily by others.
If your 12 year old son is 210 pounds, he will not die. This is because the ideal weight is dependent on the height of the individual as well. The average weight for a 12 year old boy is about 89 lbs. Your son may be overweight, therefore he needs to cut down on the amount of unhealthy food he is eating and exercise to live a healthy life.