Husband had colonoscopy two days ago. still having bowel movements more than usual. is this normal?

Yes likely: having residual waterry stool after colonic lavage is common, but should resolve in few days. If persistent beyond this, be sure to contact ur Doc. Avoid milk for now, no artificial sugard (incl diet drinks) and avoid high fructose. Can use bananas or fiber supplements to improve bulk. Red flags for urgent MD attention would be weight loss, signs of dyhydration, persistent blood, fever, pain.