The person in question would like to improve in meetings/interviews. My term "meetings" includes scenarios like code reviews, live debugging etc.
The person in question has never been a manager and (afaik) is not interested in being one. And it is difficult to avoid some of these scenarios.
I may not have worded the question well. The person in question is able to "think quickly" if they are not in a live situation. So the challenge is how to reduce the panic (or whatever word describes the feeling) that inhibits their normal thinking.