I think a lot of people would want to reply and help, but without knowing details, it would be impossible.
Details would be things like: What did the doctors say, what are the symptoms, and how long did he have these symptoms etc.? The important thing is to gather all the facts. Such information then can sometimes help erase or reduce the fear.
A lot of times, our fear can be our greatest enemy, more than the condition itself. How many times have we worried about nothing, and at the same time ignored things that are important?