The earlier response is correct. We cannot help you with any specific. Certainly, you need to restate your thesis, and when I say "restate," I mean say what your main idea is in a different way. I have found that some students think that a restatement of the thesis should be in the exact same words, but that is what you do not want to do!
Of course, a conclusion, like any other paragraph, must be more than one sentence long. Therefore, you need to know what else should or can be included in a conclusion. You should have a review of the points you made in your essay. For example, if I had three body paragraphs in my essay, I would review the three points I made in those paragraphs. Sometimes a conclusion contains a lesson that the writer has learned in the process of writing. For example, in the case of your particular topic, you might now have greater insight into what makes a father good or bad.
Remember that the conclusion is meant to wrap things up for the reader and end the paper in a graceful way, not too abruptly. Just as an introduction is meant to allow the reader to become acquainted with your ideas, the conclusion is a way of saying goodbye to the reader.
I have included a link to a site that has good advice on writing introductions and conclusions. Good luck!
It is really not possible for anyone to tell you how to conclude your essay unless they have seen your essay. A good conclusion has to in some way go with the rest of the essay. Usually, it will restate the main idea of the essay as a whole and sort of go over the major argument that the essay has made. So unless we know what major points or arguments you have made are, we can not know how to write a conclusion.
So all I can suggest is that you should think about what your main point is -- why is Rahim a better father than Baba. Then try to figure out a good way to restate it.
I'm sorry I can't be more specific -- perhaps if you let us know more about your essay...
Rahim's final act that could be viewed as fatherly is to unite the two sons together. They are not Rahim's sons but Baba's children, one born from a marriage and one born to a Hazara woman. However, Rahim still knows that it is up to him to help both boys. By helping Amir learn the truth he sets him free, and he hopes to get help for Hassan. He does not know he is dead at the time. However, his unselfish actions are fatherly for both boys. Unlike Amir's true father, Rahim has called Amir home to do the one thing that can set his soul free and help him end his oppressive guilt. He has known all along what had happened to Hassan as Hassan had told him.
The letter is in many ways was a gift to Amir. It was sent to him before he went to Rahim but it is significant enough to note. In the letter Rahimtells him that he had felt sorry for the harsh way Amir's father had treated Amir. He also gives him some knowledge of Amir’s father’s goodness.
I would try and tie these things together in the conclusion.