Dakotasmamaw - thank goodness your husband went in for the colonoscopy - and that this was found BEFORE there were symptoms! The chance of recovery is so much greater when things are caught early like this!!!!
Of course your husband does not want anyone else to know. He is a strong man - and right now, it feels to him as if this cancer is taking away his identity as a strong man. He feels overcome and terrified, probably, since that is the natural reaction. And he doesn't want people to look at him differently now.
You will have the meeting with his physician, and options will be given. Then, you can decide if you want a second opinion. Or you may already now that you want a second opinion, and will set one up.
When you do decide on a course of action, please arrange for as much support as you can (for you!) You know that the hospitals have social workers (free for patient families). Call them, sit outside their office, get them to tell you what support groups and services are available to you. You need to take care of yourself, so you can give your husband all the love and care he needs!
When one of my family members received a diagnosis like this, I immediately called my internist. I got an "urgent appointment". I told her that I was feeling terrible anxiety and I thought it would interfere with my ability to take care of my ill family member. My doctor told me that there are 4 anti-anxiety medications which are very effective. She gave me a prescription for one, and said if that one didn't help within a few days - to call her. And we would try the others, until we got one that worked on my system.
This is something I needed to do for myself, so I could function calmly and with good judgement. I did not want to waste my energy on being anxious. You may not need this kind of help. But please do get all the help you need.
Now about your son. You husband wants to spare him worry, because he loves him. But you would not want your son to keep such a secret from you, in order to protect you from worry. If your husband does have surgery, your son will learn of the situation. This is an opportunity for your son to grow as a man, and to show love for his parents. Perhaps this is the reason he was sent back to live with you both.