What i think happened to sages brother.

[Evolved]

I think after they sealed the juubi into them the sages brother could not control it and was killed by the So6P. Which is why his brother was forgotten.

 

[DeMaggio]

okay sure...

 

[Evolved]

okay sure...

I just want to see the sage fight his brother now...lol

 

[Sir Blades]

That made no sense I started to uncontrollably laugh XD

 

[Queen of Saigon]

killed who? what????????

 

[Nazaki Uchiha]

Hagoromo spread his share of the juubi's sealed powder into 9 bijuu and his brother sacrificed himself to forever seal the juubi into the husk????