Its amazing the way she is handling Arman. If somebody attacks you, there was no need for you to get exasperated. Most lack in judgement when they attack. It is actually very difficult to refrain oneself from attacking back.
I think, knowingly or unknowingly, she is going in the right direction by telling him in a non aggressive way how he feels about him abusing her. Here I feel she is not doing it frequently enough and also she should be more firm about it. It is very easy to just ignore him walk away or even abuse and scream, but that will not bring a change in him. Sometimes, it takes a lot of patience and handwork to build a relationship. If your friend is sick its alright to walk away form him and leave him alone as his sickness can also affect you but its far more greater to take care of him leaving your self interest aside. This is not being a doormat but she is doing a huge favor for arman and that is how strong relationships could be built. Of course, Tanisha may have many other things in her to change or work on but this quality of her amazed me. Following is one message from Eknath Easwaran which I would like to share,
It is so easy to say something at the expense of another for the purpose of enhancing our own image. But such remarks, irresistible as they may be, serve only to fatten our own egos and agitate others. We should be so fearful of hurting people that even if a clever remark is rushing off our tongue, we can barricade the gate. We should be able to swallow our cleverness rather than hurt someone. Better to say something banal but harmless than to be clever at someone else's expense.
Ekanth Easwaran, Words to Live By