Trying to help a family member and don't know how to advise. Divorce decree says ex is to provide health insurance for her child. He has done so for most of the time since divorce (several years). His coverage is always out-of-network for child since the parents live several hours apart. Btw, they have joint custody with my family member being primary residential parent. My family member has had family coverage with her new husband for several years which also covers her child from previous marriage. Due to birthdate rule, ex's policy would be primary so they just never listed it and used the new husband's policy only. Dumb! What should they do now? Once I pointed out that they were doing it wrong (just went through my own divorce and discovered this), they're panicked. They don't want to keep doing it wrong, but are afraid to just start listing both insurances for fear it will be discovered that the coverage was there in the past and not mentioned. Any suggestions? I don't want to tell them to do something and then have all the costs of the old claims come back to them or even get into something that could cause criminal issues. Should they just consult an attorney first? I'm at a loss of how to help.