Legal Question in Family Law in Montana

Your best bet is to speak with an attorney, take in all your documentation including the entire court file if this has been in court, and get legal advice on how to proceed. If you have a parenting plan (custody order), and if the father is not complying with the order, you can file a Motion to Enforce Order. "Abusive" is pretty vague, but if father is physically hurting the children or neglecting them, and if you can provide solid evidence, you could ask an attorney to help you modify the parenting plan. If the children are old enough, some judges will speak to them in chambers (with only the court reporter and Judge's clerk present).