My Dear Brother,
At first, I confer my blessing on you. I learn from the dad that you are appearing at an examination, next week Dad says that you have very nervous over it.
Brother (Name), please be sure that there is nothing to be nervous over. Examination-hall is only a hall, where the candidates sit for the examination. The invigilators are not your enemies. They are rather quite sympathetic. They are to help you in getting paper and drinking water. They may be terror to the bad candidates who adopt unfair means in the examination-hall. But they are quite sympathetic and kind to the good and noble students of your nature. Please do not get nervous over the question papers. if they are difficult, they are equally difficult to all the students of your standard. Hence do not be nervous. Please convey my best regards to our mom and dad.
Your Loving Brother