We were never told how high or what the rate on either the LDL or HDL were. I'm pretty sure it is a genetic problem, nearly everyone on my family thin or not is warned , or on med's for it. My father, and grandmother both passed from Heart problem which are actual quite prevelant in our tribe and Native American's in general.
I don't know if your doctor was using scare tactics, he may also have been speaking reality. What you don't tell us is how high your son's cholesterol was. If it was just a little too high, then yes some lifestyle changes may be sufficient. Diet and exercise may be enough to get his levels where they need to be.
However, if his number, particularly his LDL is very high, then medical intervention may be necessary. Cholesterol lowering drugs are very safe and the side effects are almost all very minor and the odds of a serious side effect are very low. Yes, cholesterol is necessary for proper brain function, but what no one knows is how much is necessary. How low is too low?
Take a look at the link below as it summarizes all the studies that have been done and the relationship between high cholesterol and heart disease;
http://www.jewishhospitalcincinnati.com/cholesterol/Research/ROLE_LDL_CHOLESTEROL_HDL_PREV_CORONARY_STROKE.html
First of all, the physician was using scare tactics. I am sure he meant well, but I would certainly do a bit of research and get a second opinion. There are two "universes" of individuals. Those who can handle high levels of cholesterol and those who cannot. Do a search in the magazine "Scientific American" for some excellent articles on this. This is genetic. In recent years there has been a test developed to distinguish between the two, but unfortunately it is not routinely given. There are significant problems with cholesterol lowering drugs. They do dissolve cholesterol, however cholesterol is also used to store memory. That being said, it is not a good thing to be overweight. A common cause is a malfunction of the endochrine system, which controls metabolism, so before going further I would have him evaluated by a specialist called an endochronologist.