Why would a Father do this???!!!!WTF

Sorry its soooo long...It's too many details but I'm going to try to sum it up. I have 2 children by this man, 7yr old girl and 3yr old boy. We now live in different states. He has always been an inconsistent and unreliable father and comes around when he wants and takes care of them when he feels like it. 2 yrs ago I decided to finally take him to court and he then started getting the kids during summer and holiday breaks. 
So after my kids returned from thanksgiving break last yr my daughter told me he older half brother who is 9, had touched her with his hands in her vagina multiple times even though she asked him not to. She was scared to death and embarrassed bc she knows no one is suppose to see or touch her in her private areas. She was also very confused bc she said it hurt a little but in a way it felt good too, she was even more embarrassed about that part. She was scared to tell her father and her brother begged her not to, keep in mind she was 6 at this time so she was very confused and shut down.Needless to say I took her to the doctor immediately, they reported it to authorities and she has been in counseling since which has helped her sooooo much. She felt a lot of guilt bc she didn't want to get her brother in trouble bc she loves him but she didn't understand why he would do that to her. 
She has not seen or had contact with this brother bc the doctor and authorities advised against it, I wouldn't allow it anyway, and she has no interest in being around him. But her Stupid father doesn't seem to get that. 
First he responded horribly by shutting her out and being more concerned with protecting his son and not at all concerned with how she was affected by the incident. He just acted as if nothing happened!! Now months later he keeps pressuring her to speak to her brother and says he doesn't want this to stop them from knowing each other and having a relationship. He even text her behind my back telling her she should go to his house so she can play and talk with her brother! WTF is wrong with him? I know he is a kid too and the authorities, doctor, and myself all recommend he get the boy some counseling but they have done nothing! I feel that's unfortunate but not my problem, my concern is my kids and I don't feel he should be pressuring her to see or speak to her brother at all. Am I wrong? Is there something I'm missing that makes what he is doing understandable? Bc I don't get it!!!