We don't deny that he can remember dream| having dreamt so & so before he was born. Denying this to us would be like denying that he can say he remembers having dreamt so & so before he was born.
     I.e. we don't deny that he can make this move but we say that the move alone or together with all the sensations, feelings etc. he might have while he is making it does not tell us what game it is a move of.| to what game the move belongs.
     We might e.g. never try to connect up a statement of this sort with anything past (in an other sense). We might treat it as an interesting phenomenon & possibly connect it up with the persons ¿writing¿ in a Freudian way or on the other hand we may look for some phenomena in the brain of the embryo which might be called dreams etc. etc.. Or we may just say: “old people are liable to say such things” & leave it at that.