My husband had gallbladder surgery 5 days ago and experiencing extreme nausea, is this normal?

No. No, it not normal. However, 35 % people have post operative nausea and vomiting. He can take zofran (ondansetron) but the most important thing is to call the surgeon or gastroenterologist who did lap. Chole. Or open surgery. Post op complications do happen.
Post op nausea. You should meet with your surgeon to discuss. But a small amount of discomfort , cramping , nausea and even pain at the port sites or in the abdomen is normal after this procedure it may even be related to the pain medications, best to discuss with your surgeon.