I experienced the same a couple of years ago. Diagnosed with chronic severe vertigo (lasted for about 10 mos.) was given a Rx for severe dizziness & physical therapy at an ear specialist clinic. Was told not much they could do. Would have to live with it. However, I noticed I experienced vertigo more often when I had sinus related symptons (i.e., migraines, congestion, itchy throat & ears) or when the barometric pressure dropped usu. consisted of rainy days or thunderstorms. (I know...the weather? sounds unusual, but it was accurate.) After the antibotics & steroids for sinusitis then my vertigo subsided. In that year alone, I visited the dr. 5 times for sinusitis. Before this I never visited the dr only for my annuals exams. Last week, I fell playing soccer with my son & everything started to "spin." I used my neti pot & took some OTC sinus meds & it's gone. Last week, the dr's offices were filled with sinus related problems. Also, I noticed when I cried a lot my vertigo would get worse. For me, I believe it's the drainage in my sinus cavity. Either fluid remained in my sinuses when I cried & it wasn't until I flushed it out with the neti pot would it improve. Would strongly recommend a neti pot & just flushing out the sinuses on a daily basis and see if vertigo subsides. I'd give it a couple of weeks. Hope he gets better...I know how frustrating it can be. I'm a mother of 3 and that year was the hardest year for us. When I was down this house shut down completely! Good luck...