Dear Dr. Riachi,
Words can't really fully express how grateful I am for all of your help. I am touched by your care and generosity. I apologize for being so stubborn and difficult at times, but the fact that you listened to me, and to my concerns, really showed me what an incredible person you are.
I can't thank you enough for doing my surgery, and for doing it better than I ever could have imagined. You turned what could have been an awful experience into an enriching one. As it taught me not only a lot about myself, but also a lot about the goodness of the human heart, which you showed me through your friendship.
I will never fully be able to repay you for what you have given me, but I pray you know just how much your kindness has touched me. I feel very blessed to know you. You have made a difference in my life and in the lives of many others. You should be very proud of yourself. You are truly a wonderful person.