I think for some people, diagnosis, the attendant statistics about surivival and treatment are so scary that they really can only cope by clinging to something that sounds optimistic (like that someone told him it will be a piece of cake) and ignoring everything else that might contradict it. And it isn't always the patient either. I was definitely not this way but my husband WAS at first, and this was confounded by disagreement among my docs (mainly with a radiation oncologist who later, I heard was fired-he certainly left very quickly) because the RO was saying this was early stage cancer and so would definitely not require radiation let alone chemo. Then when a second opinion from Dana Farber set us straight on that, my husband didn't want to beleive that, then when he reluctantly agreed we should take their advice, he was sure this was something I could get through pretty much on my own without any help needed including his, because he had a colleague who had gone through all of her breast cancer radiation wihtout much help (uh, so did I, it's a totally different level of ordeal). I begged him to get on here to read what other people who had been through it had to say about treatment and he continually found excuses not to. So need less to say, my entire treatment was also a process of him coming to grips with a reality much worse than he thought it should be even though he had been repeatedly warned about what it would be.
It did not do wonders for our marraige and he admits now he wasn't the supportive person he should have been because of that attitude. Under other circumstances, you might call it optimism but when it gets extreme, it can get in the way.
Anyway, at least your neighbor has you to turn to for advice during treatment, however it actually turns out to go for him.
Nelie