<prompt> Human: My sister is having a rough time and will be taking a year off college. Home is not the best situation for her for a variety of reasons so Im looking into having her move in with me 27f for the year and providing some structure. Were in agreement that shell need some mental health outpatient treatment while shes here. Problem -- shes under our fathers health insurance PPO, but there arent any in-network providers in my state. Im looking for information on adding her to my insurance is this possible? Some initial research indicates no... or other steps we can take to minimize her healthcare costs while shes in my household.Any advice you can give is much appreciated!  <response>: With her being on her dads insurance, that will be considered her primary coverage. Standard for coordination of benefits since she was on that one first. Depending on your employer, the dependent coverage definition may be different than what you have found online, so it would be helpful to reach out to your insurance company to go over the dependent definition in your plan. Also keep in mind she would also have to meet a new deductible for herself before coinsurance kicks in. You might also want to research behavioral health providers under your plan as well to make sure she can definitely get the help she needs and that they are in network. If you are not able to add her to your plan, you can always ask your insurance company if they have any self-enrollment options for shortlong term options, and also get with your father about the situation because more than likely if she goes for treatment he may be sent a portion of the bills and explanation of benefits to his address on file. If he is willing to have her removed from the plan, then that will help as well. Hope that helps! 