There really isn't adequate information here, but the following may help:
1. If she sold half the house, then there should be no CGT, as it is her principal private residence, and she has sold part of it. I am assuming that she sold, as stated, a subdivision of the house. Different considerations apply if what she sold had a development value.
2. As the court found in the brother's favour, it must have found that he was beneficially entitled to half of the house. In the circumstances, it seems far more likely that the sale of half of the house would have consititued a disposal by the brother. If the house was not his PPR, then this would indeed have triggered a CGT liability - but for the brother.
The solicitors who handled this should be able to advise; Some solicitors do not deal with CGT issues, but at a minimum they should be able to source proper advice.