What Causes Dizziness While On Lisinopril And Megafit For Malaria?

Hello, so my dad who is 65years old threw up some days ago and while he was, the centre of his head was swelling up frightfully. My mum was there so she immediately began to push it back down. The doctor diagonised him as having Malaria ++... and his blood was very dark and thick. He was given some drugs to take and is well on his way to getting better. The problem now is that he is experiencing dizziness everytime he stands so he finds it difficult to walk around easily now (every other symptom is gone except for the dizziness. He is still on medication though) ..also he hears a buzzing noise in one of his ears for a while especially after phone calls... What do you think is wrong please? He is taking LISINOPRIL TAB usp 5mg, MEGAFIT, LONART TAB + INJECTION...that s all. What do you think is the cause of the dizziness? Is there a way to make it go away?