The dislike of a step-parent by a child alone may not typically be considered sufficient grounds for modifying custody arrangements in family court. Custody modifications usually require a significant change in circumstances that directly affect the best interests of the child. The courts prioritize the well-being and best interests of the child above all else.
However, if the child's dislike of the step-father is indicative of broader issues within the family dynamic or if there are concerns about the child's welfare or safety in the presence of the step-father, then it might be worth exploring further. It's important to consult with a family law attorney who can review the specifics of your situation and provide guidance on whether seeking a custody modification is appropriate and feasible based on the circumstances. Additionally, family counseling or therapy might be beneficial for addressing any underlying issues and improving relationships within the family.