The sterol which is contributing to his high risk for coronary artery disease is cholesterol. There are said to be two major forms of cholesterol. LDL is the bad form and HDL is the good form. The reality is that the cholesterol itself is the same in both forms. The difference between the two is the density of the cholesterol contained in the lipoproteins that transport them through the bloodstream. LDL's have a higher percentage of cholesterol than HDL's. Another difference between the two is that HDL's help to bring cholesterol to the liver for chemical processing, thereby reducing the cholesterol content in the blood.
Cholesterol in general is found in any food containing animal fats. Meat and dairy (eggs and cheese in particular) contain cholesterol. Plant matter (fruits and vegetables) contain very little to no cholesterol. One particular bad food source linked to elevated LDL's are trans fats. Trans fats are mostly created in chemical processes and are therefore mostly found in highly processed foods like fast food and snack foods.