Great Niece.
natini
4 daughters, 3 sons.
Your brother's daughter is your niece..and you are her AUNT.
The relationship to you would be your cousin !
your 5th cousin
Cousine
It's called the daughter-in-law.
She would be your great grandmother
YES
Yes, she did. She had the relationship of a mother that a mother has with her son. As most mothers do.
NO
You are their aunt or aunt by marriage.