Hi, My Friend Has Been Suffering From Severe Dizziness, Sensitivity

Hi, my friend has been suffering from severe dizziness, sensitivity to light, nausea causing severe vomiting and dehydration for the past 9 months, twice he has been hospitalised as he could not stand up and had been constantly vomiting for more than 5 hours. He has been diagnosed with vertigo and takes medication twice a day but he is still suffering from episodes, he is having so much time off work as he is unable to function properly...please help