A bit of background, DS is 6 and we've been going through the assessment process with him for nearly 3 years! We've had several stints of "wait and see" but as he gets older it's becoming more obvious that he just isn't quite like other children his age.
We also have an older DD 8, who is finding DSs behaviour hard to take, especially at school. She knows that he's been with us to a couple of appointments but we've not gone into it in detail. Just told her we have having problems with A's behaviour and are visiting X to see if they have any ideas to help us.
We've tried not to get too specific with anyone until we actually have a diagnosis. In many ways I expect we'll keep it that way, it seems better to just explain he has difficulties with XY or Z and we handle it like this. However I'm feeling we may need to explain a bit more to both children soon.
How have others gone about telling the child and their siblings? Any books (especially for the oldest) which people think are useful?