The eternal question - what to tell the children?
In general, I don't advise telling kids that they have been accepted into DYS until there is some concrete need for them to know, or at least a concrete event to attend, or some change in their life that springs from this identification.
I don't mean this as criticism Jrl - it sounds like your son is very much in need of knowing that he isn't all alone, and that he has a very concrete way to understand DYS - it's what his older role model belongs to!
Smiles,
Grinity