My 21 y/o healthy son was at the barber and  began feeling lightheaded and it progressed to severe dizziness. His vision was very blurred and he couldnt hold his head up. he spilled a cup of water that he was given in his lap due to the severity of his dizziness. he began to sweat profusely afterwards and had a headache. I learned from him that this happened once before but he blacked out for a few seconds, falling to the ground. he cannot recall if there are symptoms prior to dizziness.
Hi, Welcome to Chat Doctor forum.  It appears to be a postural hypo tension, due to weakness of the nerves, or anemia etc. The other cause may be the epilepsy, it is a disease with excitation of the brain. He may need to have E.E.G, and C.T.scan for confirmation.  So I advise you to consult a neurologist for diagnosis and treatment.  Wishing for a quick and complete recovery.