hi, i'm in a similar situation. we've just been told that our older son has HFA (though no official dx as such), our youngest has asd but has communication/language probs. concerned on how to explain that he has something with a similar name to little one but why he is so different from him.
we've been told by our psychologist not to tell him anything yet but we're not comfortable with keeping this from him when others know about his condition.
we're a very open family, he knows all about his brother's asd.
upsetting me that we're keeping secrets from him but we're not seeing pstch. for another month and we've just had this dropped on us and have been left with no support or advice on how to deal with things.