Divorce in Mohammadian law

One of my friend(male) got married this year. It was an arranged marriage. The bride was in love with another person and was compelled to marry by her parents. The bride refused to have physical relationship with her husband. This continued for a period of time. The bride stills continued to talk with her lover even after marriage and planned to run away with him. One late night she was caught redhanded speaking to her lover at midnight 2 o clock. After enquiring everything, the husband took her to her parents home and left her there. Many discussions took place for a few months between both the families. And few more details like the girl having sexual talks with her lover and giving money to witchcraft people to get seperated from her husband were found on her cellphone. The husband finally decided to divorce her. In front of all the jamath/imams the husband gave talaq to the wife. The jamath held that they will wait for a period of 3 months ( iddat period). If both the husband and wife decide to live again before the iddat period gets over they can. Or else after three months they will get seperater and no longer will be husband and wife. The father of the wife is trying to create problems demanding for money. He threatened the husband by telling that i will come to your home and leave my daughter and go. Can someone give me any opinion on what step can the husband take further.