You can make a search on google and you will have thousands of them : you can try these sites if you would site 1 , site 2 , site 3 , site 4 , site 5

I hope that they are useful

An advice : if you want the best for your brother, it is better to ask him to do it by himself. No matter how hard it will be or how bad the story going to be, still it would be the right step to take. Kids and youth learn so fast in the right way or wrong one and so it is our duty to be an example and to show them the right track that they should follow. Making the story this way is an easy job but might teach the boy a lesson that you may regret it in the future. No harm meant of this advice, just love and peace