Thank you for the query.
Hypercholesterolemia, is definitely a risk factor for conditions like Coronary Artery Disease and
Cerebrovascular accidents (commonly known as stroke). Since your mother in law is 90 yrs also, she is already proned to such conditions, due to development of age related
stiffness of blood vessels. I would like to enquire whether she has associated comorbities like
hypertension or
diabetes mellitus, in which the risk of complications are magnified.
Since her cholesterol is quite high at 300mg%, I would advise you start her on a low dose of statin drugs (HMG CoA reductase inhibitor), which will help her to lower the cholesterol level. Some investigations need to be done prior to starting the medication like Liver Function test and Serum CPK. If these are within acceptable range for her age, she can be started.
Vitamins will always be beneficial for her at this age, when the nutrition of the individual gets hampered due to various reason.
Fat restricted diet (specially
saturated fat restriction) is a must for her at this stage, since it may further worsen the situation. I would also advise you to get a renal function test done for her if possible. In her case it is expected to be slightly impaired, taking her age into view.
Hope this helps you.