My Husband Had Bilateral Pulmonary Embolism 4 Years Ago. He

My husband had bilateral pulmonary embolism 4 years ago. He has factor v Leiden. Will be on Coumadin for life. He is 69. Since then he has ups and downs on blood pressure. Nausea on and off every day. Dizzy. He has been through many tests. He has two small gall stones but can eat almost anything without symptoms. His lungs survived the embolism although there is some minimal scarring. Pulmonary and cardiology say he is not serious enough and won't be to caall COPD. The cardiologist has done stress and Echo and no heart damage from embolism. What can cause this nausea? And light headed. He has sleep apnea but U.S. 100 percent corrected with a C Pap. We have readings done regularly. We just can't find out what the problem is.
Do you think it's the Coumadin it takes 10 mg a day he is 250 pounds and 6 foot three. He goes to the gym every day in walks a half hour it's 3 mph on the treadmill to try to gain endurance. He's done a wonderful job at that since his embolism. Trying to give you as much input As possible because we just can't figure out why he feel so sick all the time. Thank you for taking the time to read this. Sincerely Flora