My father has cerebral ischemia. What is the best medical treatment for this?

Mess. Controlling HTN with meds, , lipid control with meds, diabetes control, smoking cessation, anti platelet therapy, becoming active, eating a well balanced diet, etc.
Intervention . The most common cause of cerebral ischemia is atherosclerosis, a condition in which your arteries become clogged and hardened as a result of abnormal fatty deposits. Treatment requires intervention to open the obstruction. This can be surgical, by percutaneous angioplasty, or use of thrombolytics.