In some cases you can try to educate the relative, show them that your faith isn't what they think it is, the positives and how having that faith is helping you, and where their misunderstanding is based. It's always worth it to try, but also know when to walk away because you aren't going to change them.
If you have to walk away, I advise doing so completely. See and speak to them as little as possible, and make it very clear that while maybe you like them as a person and you understand their own faith you will not associate with them if they have a refusal to understand yours as well.
You're living with them I assume based on the wording of the question, and in that case there's even less you can do. If it's getting you in trouble then it's best to keep your faith hidden, even if that's hard. Fake being part of their faith if you must and if it'll keep you safe while you have to live with this person. If they refuse to learn and understand even after your attempts at education then honestly just move out as quickly as you can and cut them off - family is not blood, and you are not bound to them just because of it. If they're making your life miserable in any manner you have every right to walk away as soon as possible, letting them know why you are doing so and giving them a chance to realize what they've lost and get back into your life but also know when to cut off if they're not being genuine about it.
Do what you can but don't try to force it, hide if you must and trust in the understanding of who or whatever you worship to keep yourself safe, and if they won't understand get away as fast as possible and as completely as possible. You'll be much happier for it.
