Hi Keith, I don't have a lot of experience with this directly, but my husband was on chemo for awhile...and he did get forgetful about short term things, and also would say wording that was slightly "off" like using one word when he meant another, or commenting on something he was thinking about rather than answering what I or another person was talking about.
Somewhere on other cancer info site, I read about the state of "chemo brain" and some explanations that made sense. My husband would even joke about it a little. when he did something strange or couldn't remember, he would just shake his head and say "chemo brain."
I think if you did a Google for the term "chemo brain" you'd find some resources. The basid theory seems to be that if chemo is circulating throughout the body, then naturally it will hit some brain cells. Also the body/brain is adjusting to extra substances being in the bloodstream, and the systems just get tired out occasionally.
I hope others have additional info...sounds like a "normal" reaction given the circumstances...:(