DH's parents are divorced and MIL lives with new partner, who ds calls uncle X (they've been together for about 8 years now). BUT now, our son is 2 and suddenly MIL has started sending Christmas and birthday cards signed "grandma and grandad". DH had a quiet word and she made some crappy excuse about writing it 'by mistake, but what difference does it make'. How do we tell her that writing something down doesn't make it the truth and to just accept that DS already has 2 grandads?