Islam cares about the human relationship that should be based on kindness, care, cooperation, and solidarity. Muslims should be caring and loving toward one another. Such manifestations of human relationships should involve the relationship between wife and her parents in-law, which is a very special relationship.

Dr Zeinab  Al-`Alawani, instructor of fiqh and Islamic studies, Graduate School of Islamic and Social Sciences, stated,

Islam calls our attention to the importance of human relations in life. I am very sad that many of Muslim’s concerns revolve mostly around the halal and haram, while disregarding the significance of human relations in life. Respect, kindness, cooperation, love, care, support, and solidarity are just some manifestations of human relationship. It is not healthy to always think of anything as either halal or haram, or whether you are obliged to do it or not, because life is based on many aspects.
Having said that, the relationship between a wife and her in-laws should not be looked at from that perspective. This relationship should be based on mutual respect, love, and kindness. Islamic values like caring for the old and having mercy on them should not be disregarded when there is a problem in the family.
We know that our parents sometimes make mistakes, as we also make mistakes sometimes. But this should not affect or change our relations. The wife should treat her in-laws the same way she wants her husband to treat her parents and family. For example, would she like her husband to be nice, caring, and loving to her parents? If yes, then she should treat his family the same way.
In the beginning of my marriage, my mother-in-law (may Allah bless her soul) was sick and I did my best to look after her and support her in times of need. Now, my mother is sick and my husband is doing all he can to support me and assist me in whatever way he can. This cooperation in times of adversity adds to the quality of life. I hope we can work hard to live by Islamic values, so that our relations become better and the tensions in our families fade away.