The epley maneuver is to treat BPPV- where an otolith becomes dislodged and then finds its way into a semicircular canal (normally the latteral canal). If it was causing vertigo it would have to be the posterior canal. Not to say it isn't possible, but it is the statistically least common canal to happen in. Not only that, but the epley wouldn't treat it. Even then, this strongly doesn't sound like BPPV, whose episodes would last seconds to minutes. If the episodes are lasting minutes to hours it is a short list of other possible things. best case this is vestibular migraine of it was vestibular related. More likely this is central involve ment and the person needs to see a neurologist. I have seen patients like this before for balance accessments. We will do the testing on them(VNG and caloric testing), but then have to tell them to go to a different department because it isn't part of the vestibular system causing the problem. I would push to see an ENT/neuro/PCP sooner than later because worst case is it is a developing vestibular schwanoma (non cancerous tumor) and the sooner the better to take care of it or at least monitor it.