I can't speak to the OP's situration, but if one of my brothers made the conscious decision to fraudulently open accounts in my name I would fight the fraud as hard as I could until it was completely removed from my record and let the CCC's and legal system sort him out.

It wasn't a simple mistake, it was a decision he made to defraud a family member. IMO he doesn't deserve any different consideration than a stranger doing the same thing.