He is complaining of a problem between his wife and his sisters

Praise be to Allah.

Allaah has enjoined upholding of family ties and kind treatment of one's wife. We will never tell you to sever your ties with your sisters or with your wife. Rather we tell you: bring them together and do not make the division worse. 

Love comes from Allaah. He has created causes of love and causes of hate. So you have to look at your relationships and seek out the causes of hate and enmity so that you can remove them. And you should try to bring in the causes of love so as to encourage it. These causes include: greeting with salaam, giving gifts, visiting people when they are sick, helping at times of need, and many other things which Islam tells us strengthen bonds and generate love among people. 

In order to calm both sides down, you also have to remind each of them of Allaah and His warning against gossiping, insulting, slandering and interfering in people’s private affairs. 

Adhering to the limits set by Allaah and giving each party their rights, and respecting the rights of the other party and not belittling them or annoying them, will also guarantee happiness and peace in the house and in your relationships. 

You have to advise your wife and your siblings to treat one another well, and try to remove the problems and disputes that exist between them. If your wife and siblings are living in the same house, there is nothing wrong with you giving your wife her own accommodation, if you cannot reconcile between them. Indeed, this may be a means of removing the disputes between them. 

Our advice to your wife is that she should be friendly towards her husband’s family and treat them kindly as much as she can, without doing anything that is forbidden according to sharee’ah. Respecting her husband’s family will make the relationship between her and her husband remain as good as it can be. 

May Allaah help you all to do that which He loves and which pleases Him. May He guide you to the best of words and deeds and attitudes. 

And Allaah knows best.