Date: __ /__ /____ (Date)
Dear _________ (Name of younger brother),
Hope this finds you in good health brother.
I am writing this letter to bring some light on some important factors of life and the future. I might sound very serious and determined, or maybe not, but this is for your own good. Let me just tell you that, whenever you do something, that task is to be done with the utmost care and seriousness. Then only, you will be able to figure out the right paths.
I am writing this letter specifically to make sure that you do not wander the paths of education alone. Yes, it is true, that, you are free to choose whatever subject you want to, all you have to take care of is, the amount of effort and dedication you put in to excel in the subject. Please make sure, that you do not, fall into temptations of teenage life. I know you are growing up and you need to have fun. This will cheer you up at desperate times. But please do understand, your education life should be very different from your fun time.
You must know, when and how to choose and divide your time. You are quite intelligent and you know, what is best for you. But I was just concerned for you, so I thought I would write it up to you.
Hope you will find it useful, take care.
Wish you the best, hope to hear from you soon.
Yours ___________ (truly/lovingly),