M.C.
Take you son to see a Pediatric Ear, Nose, Throat (ENT) specialist. My husband was diagnosed with Miener's Disease which is a problem with the inner ear. There are tests that the ENT can perform.
When he has an episode, his ears start ringing, he gets vertigo, vomits, can't stand strait, and can't speak correctly. He basically sleeps for 2 days til the spell passes. He has medicine that he carries with him on his keychain so that as soon as he feel an episode coming he's ready. The medicine helps keep the symptoms at bay.
M.