So, the anal itching does sound like classic hemorrhoid. That itching is very common and they can bleed. I suspect he is worrying about polyps and this is why he requested the colonoscopy. That doctor is being very cautious and wanting to rule out anything suspicious. Colon cancer is such that early detection saves lives and once you have the colonoscopy, you have a long time to worry about it again as it is a slow growing cancer. Do I think you need it? Well, I don't know. Probably it is just a precaution and may be a bit overboard.
There is an alternative that my doctor calls poop in a box. :>) Basically, you get a kit, put this lining in your toilet, do your number two business into the lining, drop in some drops they provide, seal the bag and send it back to the lab. It's pretty accurate in the 90 percentile. The down side is that you DO have to have a coloscopy if it comes up positive on top of doing this test. I would think for you, it would save you the colonoscopy since you really just being cautious here with this test recommendation. Ask your doctor if you can do this. Otherwise, the colonoscopy isn't really that bad it just sounds bad.
What about your diet? Can you add fiber? Use the cream on a regular basis? Are you constipated or strain?