Listen to your wife. She loves you!
You are not correct. That is why they do sigmoidoscopy which is in lower 1/3 of the colon, because many cancers are in the lower 1/3 of the colon and in the rectum. You really need to have the last 1 foot of your colon and rectum checked for cancer. I agree with your wife! However, as the colonoscope is either inserted or withdrawn is when the physician views the lower part of the colon. Your doctor screwed up, what you are being told does not make sense. The colonoscope has a lighted lens at the end and that is where the viewing takes place.
I would think the barium study would be easier to handle then a colonoscopy. If you have a problem, and they could not give you an answer, it may be hidden in that last foot. What's wrong?
What makes you not want to do it? The prep? Well, I think you should get the procedure done. It's in both you and your wife's best interest; not to mention other family members.