Can you hold people accountable for the actions of their siblings?

Generally not, but in this case it is a bit more complicated, since the sibling was the most evil man ever to roam the earth.

It would have been easier if she just had admitted her brother’s wrong doings, rather then insisting that she could not believe he was able to have done the things that people said he had done. At the end of the day it is my opinion that complacency does make you an accomplice, but that is all it is, my opinion.