Sorry to hear he’s going through this. I also experienced lots of lightheadedness and what I described as vertigo while on this regimen. I had to be very diligent about keeping hydrated. I passed out once after standing up too quickly after round 5 and ended up in the ER. After 8 hours and a battery of tests it was determined that I was dehydrated and had low BP. I had been on anti hypertensive meds for a number of years. The doctor recommended reduction in BP meds and extra IV’s in the days following infusions. This helped but it wasn’t until I finished my 12th round before I felt better. They could never really pinpoint the vertigo issue other than to say that there are many side effects and everyone reacts differently. I couldn’t drive on the highway for months as the vertigo was to severe. Happy to report that a month or so after treatment it disappeared. Only lingering side effect is neuropathy in hands and feet. Best of luck on this challenging journey. Tell your husband to hang tough.