If you are seeking to prove that your ex is an unfit parent, there are a few things you will need to do. First, you will need to gather evidence. This may include testimony from witnesses, medical records, and any other documentation that supports your claim. Second, you will need to present this evidence to a judge or other decision-maker in a court of law. Third, you will need to convince the judge or decision-maker that your ex is an unfit parent based on the evidence you have presented. This can be a difficult task, but if you have strong evidence, it is possible to prove that your ex is an unfit parent.