He is in denial and there is nothing you can do but worry. But having lost 2 siblings to colon cancer his chances are very good for having it.
Men are hard to get to the doctors and once they do, it seems like they know more than the doctors or anyone else for that matter. I am dealing with a husband who won't do as the doctors tell him. He is a cancer patient twice. Once for laryngeal cancer (2010) and now for esophageal cancer (2012). I told him if he won't do as the doctors say, then I don't care. Hoping this would change, but no not really. I do care but there is only so much we can do and we have to worry about our health too. As of now, by blood pressure is out of control and nothing the doctor tries is working to bring it down. I know it is stress so now I have to think of myself too.
Hoping you get get your husband to the doctor ASAP -- Sharon