What's the optimal level of cholesterol serum? is 101 mg/dl , okay ? my father is 78 years old. he takes tonact 40 mg/ every day?

Normal cholesterol is 150- 199. It is the ratio of HDL (good Cholesterol ) to LDL (bad) that is more important. So check that. But I think he should be fine being on cholesterol lowering medicine

A cholesterol of 101mg/dl is considered normal. What your father is taking does not help in the assessment of your cholesterol level. I am not familiar with tonact. You should follow recommendations regarding diet and exercise and cessation of smoking to be sure that you have done all the right things to prevent coronary disease.