Wow, that IS scary. That's a big thing to not remember. But ... it's also a very new thing, and he wasn't in top form when he first learned about it, either. Plus, from your descriptions of him, he's used to being self-focused, so it might not have even sunk in very deeply when they met the other day just from pure habit, if that helps some. But definitely worth mentioning to the nurses, because that does seem like a lot of decline. If things are going very badly, sometimes they can taper off a treatment or two early. There are preferred protocols, but people aren't robots, and not everyone needs exactly the same thing. I know I was able to skip one chemo (I had weekly ones) and maybe even a radiation or two, but we were dealing with snowstorms and illnesses and things that we had to work around, so it wasn't like they were all 'on schedule' as it was. Life happens, and the doctors get it. Ask, and see what they say.