Ask them why. If a friend's parents or sister don't like you, they probably have some kind of wrong idea about who you are and what you're like. Maybe ask to meet up and discuss it all together and see if you can come to an understanding.
Remind them that you're here to listen, and be open and understanding as they share their struggles with you. If you've gone through something similar, feel free to share that...
Remember, you can't ever guarantee that someone else will like you. Try your best to make a good impression on them by being considerate and kind, but don't obsess over...
