Fratricide is the murder of a brother.
pup
Her youngest sibling is eight year old Noah Cyrus.
* Unfortunately yes, sibling abuse can lead to such anger the abuser could beat the person to death or, sometimes it can lead to murder. The victim of the abuser will not likely go mad, but will certainly need psychological counseling to get over the trauma.
He has a little brother called Jake.
Murder
That'd be a murder of crows.
A half brother or half sister sharing the same father is an agnate sibling. Those half siblings sharing the same mother are called uterine sibling.
Lions' children are cubs.
Sibling Rivalry
Sibling rivalry.
Aunt's grandson is called a cousin. Specifically, he is a first cousin if he is the child of your aunt's sibling. If the aunt is a sibling of one of your parents, her grandson is a cousin to you.
a group of Blackbirds is called a murder