Is it forbidden to cut ties with an abusive father who commits obscenities with his children, and would this cause the wrath of the Most Merciful and a bad end?

If the father reaches the point of transgression and assault on his daughter's honor and sanctity, then it is not permissible for her to sit with him alone or to appear before him adorned with her finery. Rather, she should restrict herself to showing her face and palms in the presence of a mahram. As for dutifulness to him and maintaining ties, it should be at a minimum, such as conversing over the phone and continuously supplicating for his guidance.