I am adopting a baby, and I receved a call about a 3 week old baby boy possible for me to adopt. however the baby has a brother who has this type of muscular dystrophy. they are supposed to be doing some testing to see if the baby has this. My question is, is it possible to diagnose this early if he will have it? what type of test should they be doing? What are the chances he will have this?

the brothers have the same mother, but different fathers.