Does my brother's money, earned from selling alcohol and pork, become permissible after his repentance? Is it permissible for him to perform Hajj with it or establish halal businesses? And what should I do if he sends me some of it?

The condition for repentance from unlawful wealth is to dispose of it by spending it on the welfare of Muslims (for the poor or on public utilities). If the origin of the wealth was permissible, then one keeps the principal and disposes of the unlawful profits. If these cannot be determined, then one expends what one predominantly believes to be unlawful profit. If the principal itself was unlawful, then one disposes of the entire amount, based on the Almighty's saying: "And if you repent, you may have your principal sums. Do not wrong, and you will not be wronged." It is not permissible to take unlawful money if you are certain it is unlawful, and it is more cautious not to take it when in doubt, to avoid suspicion.