In school, well in the schools I taught at, the play areas were segregated by grade level. Siblings rarely had the opportunity to interact with each other at school, even if they wanted to. But in reality it was very uncool to be seen associating with your older or younger siblings. About the only interaction schooled siblings have with each other is squabbling before and after school.
Homeschooling provides for a different lifestyle for siblings.
A world where they spend most of their time with each other.
A world where they may even have the same group of friends.
A world where big brothers help little brothers.
A world where brothers can be best friends.
Who needs more reasons to homeschool!!