How can we tell our child about his muscular distrophy in a truthful but not frighteneing way?

Gently and gradually: Children have the right to know when they have a problem, especially one as serious as muscular dystrophy. However, there are various types of MS that have quite different courses. Starting with validating the symptoms as "real" not imaginary can be a great first step. Making it clear they can ask questions and get real answers is the major goal.

Gently: Tell him he is special. His muscles are different and react different than others. And just like other people we are all different in our own way.