sinuse operation and brain stroke

I knew a person who used to have low blood pressure not very frequently, went for sinuse operation whereas x ray report said that, Paranasal sinuses are well aerated and appears normal, Bony walls of sinuses are intact , Bony nasal septam is in midline, Turbinates hypertrophy is noted bilaterally. Everything before and after operation was normal,but nasal bleeding continued for 10 days ,for he took anti biotics and still some infectin was found for that he was prescribed another course of ani biotic. Just after taht he got severe cerebral stroke, he fell down from the standing position suddenly , admitted in the nursing home.. kept in the ventilaton for 4 days  but in sense less condition and expired.. my question is that is there any relation between sinuse operation and brain stoke?