If your sister did not lure her friend’s ex-husband nor seduced him; rather he left her on his free will without any fault of your sister, and she married him after his divorce, then that woman is irrational and unjust. Your sister is not to be blamed; if she could not live with him, it is not your sister’s fault.

 

If your sister did no wrong, she does not need to brood over this issue. She should only leave her alone and ignore her.

 

By failing to do that, your sister is letting her friend control her life. It will only increase her agony. And she will never be able to enjoy peace with that kind of attitude.

 

Allah Almighty knows best.