Can he say what he was thinking about a little while later when the conversation has moved on and when that thought is no longer relevant to the discussion or is he holding onto too many trains of thought at one time and following at least one other persons, usually a few more, trains of thought simultaneously in a conversation;Then whatever he was thinking is just irretrivibly gone until he gets de ja vu' from a similar thought in a different context?

Youth lives by personality, age lives by calculation. -- Aristotle on a calendar