Decvorce from sick wife
My brother got married(as per muslim rituals) in Feb 2016 and from the second day of marriage we get to know that the bride is ill as she falls suddenly wherever she stands and this happens 3 times in front of us within a weak. Also her behaviour was very unexpected and she is not accepting my brother as husband. Within 20 days of marriage her sickness getting worst and she is not able to stand properly and lie down whole day unconsciously. We Consulted with doctor but she didn't get well, then we send her back to her father's home as if something happens wrong then their family member will going to blame us.
Later we get know that she is ill from long ago and her father already did whatever he can(cure from doctor and astrologer both) and she is suffering from some paranormal activity and her father is consulting with some astrologer/maulana/mufti etc but no result yet.
Another thing we found is that, we have recorded her call and found one doubted call in which she is talking to some person and her discussion seems that she is cheating with my brother and have some relationship with other person as well.
Its been only two months of marriage and she is staying with her father from last one month but her condition is getting worst and we stuck to what to do. Few days back we asked her father to give us divorce as this is not making anymore but he is asking for more time to resolve the issue. Please suggest me our next steps to follow and how we can get devorce from her?