Basically this is my first Christmas with my 2 children. We are meant to go to my mum's and brother and sil and their 2 children are coming home (live in another country) this will be first time my children will meet my brothers family. However i just found out SIL wants to bring her niece as well. All our children apart from the sil niece the niece is 14. How can talk to my brother as i feel it might be bad choice for the first visit.