Hi, thanks for asking from HCM. I can understand your concern. The episode of sudden imbalance in a 61years old male could be due to : Low blood sugar as you mentioned : Transient ischemic attack - It is sudden decrease in oxygen and blood supply to brain. It is temporary and patient recovers on its own. But in long term, it can cause stroke : Dehydration and low BP as you mentioned - It could occur following poor fluid intake, exertion, sweating. Sometimes it occurs following loose stools, vomiting. : Ear disease - Inner ear has centre for balance. Disease of it like vedtibulitis or labyrinthitis can cause sudden fall. You should ask him to consult doctor to rule out above disease. The doctor will examine his nervous system, ear and vitals. Investigations like : CT and MRI brain : CT of mastoid and ear bone : Vestibular function test : Ultrasound Doppler of neck vessels : Blood sugar It will help in reaching some conclusion. At home, ask him : Take rest : Drink fluids reach in sugar and electrolytes if no Diabetes : Lie supine to normalise BP : He can take tab Betahistine if vertigo, after prescription. Hope it will help. If doubt, ask another question. Thanks