Thanks for writing to health care magic.
This could be because of various reasons. Involvement of middle ear could be responsible for vertigo
Does he have any paleness of the palms and soles? Anemia
could be responsible for that problem.
Was his blood pressure checked at any time? Hypoglycemia
can also be responsible for problems like that.
Please get him examined by your doctor once to arrive at a correct diagnosis.
Continue to ask further queries as required.
Hope this helps.