What Causes Vision Impairment And Insomnia After Spinal Surgeries?

Yes, my brother has had 2 spine surgeries within the last 4 months. Recovered beautifully until approximately 5 weeks ago and began to digress. He was diagnosed with a blocked vertebral artery and prescribed aspirin. Also, experienced a bowel blockage, subsequently a duodenal ulcer from nsaids. Hemoglobin went from 15 to 5.7. Currently experiencing vision impairment, inability to focus, insomnia and gait/balance issues. Age 58, non-smoker, occasional beer, eats healthy and exercises.