Well, i think he's coming to some awareness without us having discussed it further. Last night he was talking about his drive to chemo today. (We live 45 minutes from where he gets chemo, I usually drive him but his treatment today is out of order and I'm working.) He decided he'd rather drive himself than have one of my family drive him - and this is not like ordinary chemo, it doesn't really affect him much.
However, when he was talking about it last night, he was talking about taking the surface streets back rather than the freeway and when I asked why, he mentioned his reaction times. So maybe he is starting to realize on his own that his reaction times are slowed, and maybe that's why all the speeding up and slowing down.