A good book that describes the family relationship between brothers and sisters is Caine's legacy, Liberating Siblings from a lifetime of rage, shame, secrecy and regret.
They where all brothers and sisters.
The brothers of your spouse are your brothers-in-law. Also, the husbands of your sisters are your brothers-in-law.
They could be brothers and sisters or the could be cousins
Hestia was the oldest child of her brothers and sisters
Sisters
Sisters.
that you're a very messed up person, don't.
Yes, she did. She had the relationship of a mother that a mother has with her son. As most mothers do.
The children of two brothers who marry two sisters are first cousins to each other. Some people like to describe the relationship as "double cousins" since most people have cousin relationships through one parent/sibling pair, and these have it through two such pairs.
Love between brothers and sisters ensures that they are supportive to one another. It also ensures they are able to protect each other throughout life.
He had 11 brothers and sisters.
Brother-in-law