How to resolve the misunderable in one family?

Hi, Sorry to hear about your relationship with your sister in law. In the first place,you guys have to figure out what is the main problem which caused a misundestanding. Of course, your brother is married and he will be more side to her wife. That is pretty normal reaction. However,since you guys not always meet up frequently, try to talk to your brother and his wife first,approach them and respect them. No matter what they are still elder than you. Try to have a good chat with your brother about this situation and from him, you will be able to know the main problem.

In laws are not easy. My partner doesn't have sisters nor brothers so I have never deal with the same problem. But here's the tip from my partner and my sisters. First of all, this is not all about you or his wife, this is about your brother too. The good relationship comes from both direction, not only one. You have to talk to your brother's wife, and tell her that you want them to be close to you as a family, so please be kind. I believe if you and your brother's wife is close each other, it will make your brother happy as well. So make sure you make this point to her, because if she loves your brother she will let your brother be happy by being close with the whole family. But I think, it's a really good start if you want to make the first move. I hope you and your family can be together harmoniously again. Good luck :)