As far as Weev himself, not much can be done. The feds are permitted to house any inmate in essentially any conditions they want as long as they meet certain (incredibly low) standards. Once you are in their grasp, you are at their mercy. Theoretically, they can keep him in segregation for the duration of his sentence. The bra thing is ordinary for jails and prisons. He is being threatened with "Diesel Therapy" - being moved from prison to prison - in order to disrupt his posts to the Internet which violate their rules.
Basically, he hasn't learned (but will soon) that he is no longer in control. The harder he fights against the rules, no matter how idiotic those rules may be, the more difficult his life will become. This is true both while in custody and during the entire term of his Supervised Release. None of this is necessary or right in the eyes of anyone with half a brain, but it is the system we have and he exposed himself to it.