You should consider yourself fortunate to be out of a situation like that. Neither of them is as mature as you are, and your life should go on having friends, not enemies with whom you must deal. If your brother ever wakes up to the situation that he is in, you will hear from him again. If not, you are far better off not having them in your life at all.

Because someone is your brother does not mean that you must love and be involved with him or with his wife. You must remember that he has chosen his path, and you have an equal and full right to choose to have healthy people in your life, not sick and mentally ill ones.

Take care of yourself and look for your friendships with mature, content people. If you are ever questioned about it at all from other members of your family, just reply that you did your share and you have nothing further to be involved with. They will receive their just punishment in time; you will eventually see what it does to them to behave in such a way.

Take care of yourself and live happily and peacefully without their problems in your life, please.