I think I have olfactory hallucinations...there are many times when something shows on the TV and I would swear I can smell it. One of the worst ones is a Wendy's Big Bacon cheeseburger, one of my favourite fast food meals (though I haven't had one since my surgery in November, have no appetite for the sodium in it!) - anyway, whenever this ad comes on TV I seem to smell it, it's a glorious smell that almost makes me want one. And when we're watching medical shows, I seem to smell that medicinal smell that hospitals reek of. I've never heard the term olfactory hallucinations, but will look it up. Perhaps he's somehow associated that smell with his first or previous episodes of passing out. The smell might not have anything to do with it, as you say, but is the mind's way of relating the experience to a previous one. Worth looking into...find out when/where his first pass-out happened. The smell could be his mind trying to tell him where to look for the trigger.