Perhaps he has vertigo? Meclizine may help him and also physical therapy. I developed vertigo and dizziness which came with vomiting. I hope t h is helps.

Am not familiar with veniz, but looking online I see it is venlafaxine in other countries (India, Myanmar, etc.). Your husband's taper was/is too fast, too steep; big clue is that his withdrawal symptoms were much improved by going back on some of the drug and even more so by increasing the dose. Most on here trying to get off/reduce venlafaxine do better with only 5-10% drops (or even less). For his dizziness, Dram*mine, or Bon*ne (over-the-counter anti-nausea/motion sickness meds; active ingredient is meclizine--as mentioned by @secretwhitepop) helped me. Or, perhaps, those acupressure wristbands (no drug in these--good if you're trying to not add more drugs to his system)?

This not the way to taper. Way too fast. Try to reason with his doctor or find a new one ASAP! There is no reason for him to suffer like this.