User blog comment:Subject 16*/Assassin's Creed: Revelations - News/@comment-3519940-20110512042233/@comment-1153722-20110512052824

The closest relative between Desmond Miles and Subject 16 is Ezio Auditore. So they are not brothers.

And Bill Miles is too old to be Desmond's brother, I think. If anything, he'll be his father.