High cholesterol can be a serious medical issue because of the long term problems that it can cause. While our understanding of this risk factor is constantly evolving, it is well known that high cholesterol is associated with increased risk of heart attacks, stroke, and other vascular complications. The especially concerning fact is that your son is so young, as the effects of any such medical condition are obviously amplified over time.
For that reason, your son should have an assessment and evaluation performed by his physician. The current guidelines indicate that the decision about whether or not to treat his cholesterol with medications depends on the presence or absence of other risk factors for vascular disease, such as smoking or diabetes.
Obviously, the more risk factors a person has, the more reasons doctors have to recommend medical therapy to avoid long term complications. Based on this assessment and other risk factors, as well as the level of his bad cholesterol and family history of disease, your son's doctor
may recommend medications or alterations in lifestyle.
Regardless of the final recommendation, avoiding fast food, getting plenty of exercise, and having a healthy diet are important for all. Please encourage your son to speak to his doctor.