First of all you need to find out the reasons for your bhabhi’s behaviour. Is that solely separation and she is doing all this for getting separated? According to your post this is the only reason. You have two ways. Firstly some one close to your bhabhi such as her mother or some friend or relative can make her understand the benefits of joint family. Secondly your family can sit together to resolve this issue but in that case all past incidents must not discussed to blame but only to explain them as problem.