How to deal with their false memories ? How do you handle it?

When my sibling re-tells stories about our childhood, it is completely different from what I remember. I usually just grey rock just to get through it but sometimes I wonder if it is a positive or negative thing if I talk about how I remember the event.

I also wonder how they end up creating these false memories when they have said to me many times that they can’t remember anything in the past. Is there a way to not agree with the false memory but also to not invalidate their feelings?