Your father had stroke due to ischemia
(less blood supply to brain. It is possibly due to atherosclerotic occlusion vessels supplying brain. Many of these small infarct areas may not produce any symptoms.
Following course of action can be considered by your treating doctor:
1 Antiplatelet drugs e.g. aspirin
if no contraindication
2 To look for and treat risk factors e.g. smoking, hypertension
, lipid abnormalities
3 Evaluation of intracranial and extracranial brain vessels